Manakel
No pugin, i started to write a tool then go oh, its just like inkscape. So maybe use inkscape instead.
basically i foresee 3 uses
theme (in the works):
take an image and layout it with named boxes so that the my gui engine (which is pretty good imo) can cut the texture up into proper components
layout:
use the inkscape boxes to positions control on different gui elements.
direct drawing (not high on the list):
I already have limited .svg to .egg (just rectangles + their quite complex matrix transforms.) Maybe drawing the gui directly in inkscape and having a svg (2d vector graphic renderer in panda3d) would be cool.