The project page for picloader and pycloader are at
https://sourceforge.net/projects/ifi-picloader/.
All the Eclipse stuff I started integrated, centralizing, and releasing under
FIRSTclipse.
There are open source compilers available for the PIC18F. The only reason we can't use these is IFI's libraries. I don't know how many linkers can use libraries generated by mcc18.
As for a central location, I think the most that is needed is that every project have a versioning system and we have a central mailing list for the projects to coordinate. There's so many projects because of the diverse implementations, languages, and other requirements.
At this point, I think what would be most useful would be if the programmers for the various projects wrote their code in such a way that the "back end" could easily be lifted and used elsewhere.