Yeah, "apt" is really the way to go, no matter what the underlying package format is (wether it be *.deb , *.rpm, *.pkg, etc). It would be nice if there were some sort of magical way to be able to handle all of those package types together, but that might be asking a little much. In the mean time there must be repositories of packages in the type needed for the specific distribution and version. apt for RPM is nearly identical in it's workings to the Debian apt, with the exception that the underlying packages are in RPM format rather than DEB format.
apt for RPM also has the dist-upgrade and I used it on my RH61 system when hooked up to the RH62 repository without any problem. But when I hooked up to the RH73 repository I was afraid that something might go wrong so I cancelled the upgrade. This is my gateway/firewall/proxy box so I didn't really want to get it into a state that it might be down for a while. Everything else went perfectly, didn't even have to touch the machine or reboot (but this is normal in Linux).