Hooray! I now have the option to build GRASS as a Mac OS X application in the GRASS source. This is only in 6.3 CVS, and will probably not be backported to 6.2 since it’s not a bugfix. For those do-it-yourself’rs out there, give it a try – either checkout the current CVS (instructions on the GRASS site) or wait for the weekend’s snapshot.
I may create a patch download for GRASS 6.2 source for those that like to stick with stable releases.