Its been a bit, but I installed R from source code and it really didn't have any problems or serious dependencies (I'm running Slackware 10.2) . I'm guessing that you're right about the RPM package causing some dependency issues so I would try installing from source and see if that works better. If you need to make a package, you could try using
checkinstall, which replaces the make install step and can make RPM packages.