Methinks that Real Time would be much eaiser to make in RMXP than RM2K3, because of the fact that you can script with RMXP. That being said, however, if it doesn't need to be scripted in, then it is much much much easier to make in RM2K3.

Either way, there doesn't seem to much floating around for either. I'll have a look around. Can't promise anything though.