So I gave up on 1.6.2 and tried on a -current box, with -current pkgsrc
and building everything from src... still no go.

x11/py-Tk seems to need/want python-pth

but

graphics/py-imaging* appear to use python - not -pth

so to find the _tkinter.so you need to use python2.3, but to get the
pthreads needed by libtcl you need python2p3.

Obviously there's some trick to make graphics/py-imaging* use the
correct python (with -pth since it doesn't work without it seems).

Clue anyone ?
--sjg