I'm currently trying to create an RPM from a tarball that uses a proprietary binary installer to dump a bunch of files in the filesystem. This installer does not let me dictate where the files go (so I can't just dump them into a build folder). What I want to know is what would be the best way to reliably package the files?
There is a utility called checkinstall that basically does this, but believe it's Makefile-specific.
However, digging a little deeper you'll find a library called installwatch. Though a little old, this can be used to wrap system calls, and hopefully tell you what is being installed where.
Your end result will not be an rpm, per se, but this should give you enough information to construct an rpmbuild(8) spec file.
Hope this helps :)