When installing xpra using your ebuild, the following ewarn message is given upon completion:

>>> Installing (1 of 1) net-misc/xpra-0.0.7.17-r1
 * Server support requires Xvfb
 * This cannot be pulled in by this ebuild

Surely this dependency should be resolved programatically?

$ mv .xpra .xpra.old
$ xpra start :7
Entering daemon mode; any further errors will be reported to:
  /home/stroller/.xpra/hex-7.log
$ cat .xpra/hex-7.log
[dix] Could not init font path element /usr/share/fonts/misc/, removing from list!
[dix] Could not init font path element /usr/share/fonts/TTF/, removing from list!
[dix] Could not init font path element /usr/share/fonts/OTF/, removing from list!
[dix] Could not init font path element /usr/share/fonts/Type1/, removing from list!
[dix] Could not init font path element /usr/share/fonts/100dpi/, removing from list!
[dix] Could not init font path element /usr/share/fonts/75dpi/, removing from list!
5 XSELINUXs still allocated at reset
SCREEN: 0 objects of 64 bytes = 0 total bytes 0 private allocs
DEVICE: 4 objects of 16 bytes = 64 total bytes 0 private allocs
CLIENT: 0 objects of 52 bytes = 0 total bytes 0 private allocs
WINDOW: 0 objects of 24 bytes = 0 total bytes 0 private allocs
PIXMAP: 1 objects of 8 bytes = 8 total bytes 0 private allocs
GC: 0 objects of 44 bytes = 0 total bytes 0 private allocs
CURSOR: 0 objects of 4 bytes = 0 total bytes 0 private allocs
CURSOR_BITS: 0 objects of 4 bytes = 0 total bytes 0 private allocs
DBE_WINDOW: 0 objects of 12 bytes = 0 total bytes 0 private allocs
TOTAL: 5 objects, 72 bytes, 0 allocs
4 DEVICEs still allocated at reset
DEVICE: 4 objects of 16 bytes = 64 total bytes 0 private allocs
CLIENT: 0 objects of 52 bytes = 0 total bytes 0 private allocs
WINDOW: 0 objects of 24 bytes = 0 total bytes 0 private allocs
PIXMAP: 1 objects of 8 bytes = 8 total bytes 0 private allocs
GC: 0 objects of 44 bytes = 0 total bytes 0 private allocs
CURSOR: 0 objects of 4 bytes = 0 total bytes 0 private allocs
CURSOR_BITS: 0 objects of 4 bytes = 0 total bytes 0 private allocs
DBE_WINDOW: 0 objects of 12 bytes = 0 total bytes 0 private allocs
TOTAL: 5 objects, 72 bytes, 0 allocs
1 PIXMAPs still allocated at reset
PIXMAP: 1 objects of 8 bytes = 8 total bytes 0 private allocs
GC: 0 objects of 44 bytes = 0 total bytes 0 private allocs
CURSOR: 0 objects of 4 bytes = 0 total bytes 0 private allocs
CURSOR_BITS: 0 objects of 4 bytes = 0 total bytes 0 private allocs
DBE_WINDOW: 0 objects of 12 bytes = 0 total bytes 0 private allocs
TOTAL: 1 objects, 8 bytes, 0 allocs
[dix] Could not init font path element /usr/share/fonts/misc/, removing from list!
[dix] Could not init font path element /usr/share/fonts/TTF/, removing from list!
[dix] Could not init font path element /usr/share/fonts/OTF/, removing from list!
[dix] Could not init font path element /usr/share/fonts/Type1/, removing from list!
[dix] Could not init font path element /usr/share/fonts/100dpi/, removing from list!
[dix] Could not init font path element /usr/share/fonts/75dpi/, removing from list!
Xlib:  extension "RANDR" missing on display ":7".
Xlib:  extension "RANDR" missing on display ":7".
Traceback (most recent call last):
  File "/usr/bin/xpra-2.6", line 6, in <module>
    xpra.scripts.main.main(__file__, sys.argv)
  File "/usr/lib/python2.6/site-packages/xpra/scripts/main.py", line 126, in main
    run_server(parser, options, mode, script_file, args)
  File "/usr/lib/python2.6/site-packages/xpra/scripts/server.py", line 304, in run_server
    import xpra.server
  File "/usr/lib/python2.6/site-packages/xpra/server.py", line 19, in <module>
    import Image
ImportError: No module named Image
xpra: Fatal IO error 11 (Resource temporarily unavailable) on X server :7.
$ xpra list
Found the following xpra sessions:
        DEAD session at :7 (cleaned up)
$

Resolution:

…
>>> Installing (1 of 1) dev-python/imaging-1.1.7
 * Compilation and optimization of Python modules for CPython 2.6 ...    [ ok ]

>>> Recording dev-python/imaging in "world" favorites file...
>>> Auto-cleaning packages...

>>> No outdated packages were found on your system.

 * GNU info directory index is up-to-date.
$ xpra start :8
Entering daemon mode; any further errors will be reported to:
  /home/stroller/.xpra/hex-8.log
$ cat .xpra/hex-8.log
[dix] Could not init font path element /usr/share/fonts/misc/, removing from list!
[dix] Could not init font path element /usr/share/fonts/TTF/, removing from list!
[dix] Could not init font path element /usr/share/fonts/OTF/, removing from list!
[dix] Could not init font path element /usr/share/fonts/Type1/, removing from list!
[dix] Could not init font path element /usr/share/fonts/100dpi/, removing from list!
[dix] Could not init font path element /usr/share/fonts/75dpi/, removing from list!
5 XSELINUXs still allocated at reset
SCREEN: 0 objects of 64 bytes = 0 total bytes 0 private allocs
DEVICE: 4 objects of 16 bytes = 64 total bytes 0 private allocs
CLIENT: 0 objects of 52 bytes = 0 total bytes 0 private allocs
WINDOW: 0 objects of 24 bytes = 0 total bytes 0 private allocs
PIXMAP: 1 objects of 8 bytes = 8 total bytes 0 private allocs
GC: 0 objects of 44 bytes = 0 total bytes 0 private allocs
CURSOR: 0 objects of 4 bytes = 0 total bytes 0 private allocs
CURSOR_BITS: 0 objects of 4 bytes = 0 total bytes 0 private allocs
DBE_WINDOW: 0 objects of 12 bytes = 0 total bytes 0 private allocs
TOTAL: 5 objects, 72 bytes, 0 allocs
4 DEVICEs still allocated at reset
DEVICE: 4 objects of 16 bytes = 64 total bytes 0 private allocs
CLIENT: 0 objects of 52 bytes = 0 total bytes 0 private allocs
WINDOW: 0 objects of 24 bytes = 0 total bytes 0 private allocs
PIXMAP: 1 objects of 8 bytes = 8 total bytes 0 private allocs
GC: 0 objects of 44 bytes = 0 total bytes 0 private allocs
CURSOR: 0 objects of 4 bytes = 0 total bytes 0 private allocs
CURSOR_BITS: 0 objects of 4 bytes = 0 total bytes 0 private allocs
DBE_WINDOW: 0 objects of 12 bytes = 0 total bytes 0 private allocs
TOTAL: 5 objects, 72 bytes, 0 allocs
1 PIXMAPs still allocated at reset
PIXMAP: 1 objects of 8 bytes = 8 total bytes 0 private allocs
GC: 0 objects of 44 bytes = 0 total bytes 0 private allocs
CURSOR: 0 objects of 4 bytes = 0 total bytes 0 private allocs
CURSOR_BITS: 0 objects of 4 bytes = 0 total bytes 0 private allocs
DBE_WINDOW: 0 objects of 12 bytes = 0 total bytes 0 private allocs
TOTAL: 1 objects, 8 bytes, 0 allocs
[dix] Could not init font path element /usr/share/fonts/misc/, removing from list!
[dix] Could not init font path element /usr/share/fonts/TTF/, removing from list!
[dix] Could not init font path element /usr/share/fonts/OTF/, removing from list!
[dix] Could not init font path element /usr/share/fonts/Type1/, removing from list!
[dix] Could not init font path element /usr/share/fonts/100dpi/, removing from list!
[dix] Could not init font path element /usr/share/fonts/75dpi/, removing from list!
Xlib:  extension "RANDR" missing on display ":8".
Xlib:  extension "RANDR" missing on display ":8".
Xlib:  extension "RANDR" missing on display ":8".
X Error of failed request:  BadValue (integer parameter out of range for operation)
  Major opcode of failed request:  118 (X_SetModifierMapping)
  Value in failed request:  0x17
  Serial number of failed request:  21
  Current serial number in output stream:  21

xpra is ready.
909 ~ $ xpra list
Found the following xpra sessions:
        LIVE session at :8
$

after running "winswitch_applet" got the folowing failure feedback:

Traceback (most recent call last):
  File "/usr/bin/winswitch_applet", line 3, in <module>
    from winswitch.client import applet_wrapper
ImportError: No module named winswitch.client

System:
lsb_release -a
LSB Version:    core-2.0-ia32:core-2.0-noarch:core-3.0-ia32:core-3.0-noarch:core-3.1-ia32:core-3.1-noarch:core-3.2-ia32:core-3.2-noarch
Distributor ID: Debian
Description:    Debian GNU/Linux unstable (sid)
Release:        unstable
Codename:       sid