Extras-devel and the autobuilder isn't that bad. You just need to come up with the packaging pieces so dpkg-buildpackage can generate the changes, dsc, and source tree tar.gz.

The alternative is to create your own repository (a set of directories at a web site) - I have one for minigpsd at zdez.org and the tools automate the Packages.gz files and such, and you can then do a .install file and it should pick up the dependencies from Maemo.