SuSE-conformant rpms from tarballs

A while back there was some discussion here about how to construct SuSE-conformant rpms (i.e., they use SuSe-standard locations and spec files) from more or less arbitrary tarballs (.tgz files). I seem to remember a reference to a very unofficial howto by Lenz Grimmer and also some tool that helps with the task. Can someone recall that information for me? I like a clean system, and installing tarballs that the package manager doesn't know about or that put files in the wrong places works against that. Thanks. Paul