The problem with what you're asking is that there are too many variables. For example, not all MPEG-4s are equal -- I know my FCP4.5/QuickTime 6 combination produces MPEG-4s that have a 1500kbps maximum data rate, but not my client's FCP5/QuickTime 7 combination. And then there's frame size, audio data and sample rates...
A lot of trial and error goes into balancing quality and file size when it comes to compressing movie files.