Does anyone have a use for a tool to assemble an RPM without using a .spec file and the rpmbuild process? I.e., something that works on a combination of pre-built binaries (in a .tar file) along with a .manifest file?

I was putting something together like that a while ago for packaging up software for internal use, that we get from outside vendors. I can dig it up and throw it on Github if anyone is interested.

I use FPM (https://github.com/jordansissel/fpm) for that and it works wonderfully. You can convert a tarball to RPM/deb pretty seamlessly most of the time.