FYI, I just joined inkscape-devel and I'm building on Mac OS X/PPC. There are some redefinitions of preprocessor macros in path-prefix.h that break the build on my platform (CREATE_GRADIENTSDIR, CREATE_PALETTESDIR, CREATE_PATTERNSDIR).
It's pretty clear that most of the paths that now point to locations inside of the application package should probably instead point to the "Application Support" directory in an individual user's home folder for application-generated data. It's less clear to me whether it's a good idea to move a number of the other resource directories outside of the app package simply to be more "mac like" (probably more trouble than it's worth).
I'm planning to spend part of the weekend working on a little extension for some linguistics features (syntax trees), but with builds apparently slightly broken on OS X (one minor change necessary), I'd be more than happy to contribute a patch, work with the Mac module owner, and test.
David Himelright