Inkscape is really rad for creating UI mockups. Unlike GIMP it allows to structure elements into nested groups/layers. Dealing with 50 flat layers isn’t really workable. One thing that is problematic for collaboration is embeded bitmaps though. By default Inkscape uses absolute paths for image links which can be a pain.
Pim Snel has created a super extension to collect all bitmaps, create relative links to them in the SVG and zip everything up. To use it, make sure you compiled Inkscape –with-python and place the two files (.inx and .py) to
~/.inkscape/extensions/. Now all you need to do before handing a project to your collegue is file>save as>foo.zip (you have to select “Compressed Inkscape SVG with Media (*.zip)” from the format selector). If your
inkex_ module isn't found, just copy it over from _$PREFIX/share/inkscape/extensions/inkex.py_ or put the extension in the system dir instead of~/`. Thanks Pim!