I don't do things with RPMs, but if I wanted to build a Debian package for my current distribution version, I guess I'd go through the usual dpkg-buildpackage route (or use pbuilder if I had root access) after tweaking the package metadata. Since I only ever back-port things (and not that often given that I may choose to run them in a chroot), I don't know how much work would actually be necessary to forward-port a package, but quite possibly not that much.
Installing the package is another matter, though. Without root access, I'd have to hope that my fakechroot sandbox is up to the task, but given that it would be the same distribution version, the chances of that are a bit higher than they otherwise might be. I suppose that febootstrap would be able to deliver the same experience for Fedora, potentially not even needing fakechroot to do an initial bootstrap.