Like all Open Source projects tpkg is a work-in-progress. We always welcome bug fixes and enhancements to existing features (although you probably should check in on the tpkg-devel mailing list before making major changes just to make sure someone else isn't already working on the same thing). But sometimes it is nice to work on something new. As such here is a list of things that we'd love to see someone pick up and work on.
We have a set of build scripts to build tpkgs for a variety of major Open Source applications (Perl, Ruby, etc.) However, that setup is a pretty big hack. Ideally we'd have some sort of ports-like system that would output tpkgs. Even more ideally this would be integrated into existing ports systems on various platforms so that we could take advantage of the work of others on getting software to compile on those various platforms. I.e. in the FreeBSD ports system we'd add a "make tpkg" target. MacPorts can already produce a variety of package formats, it would be nice to add tpkg to that list.