Not sure if this is even possible as I'm not a programer but thought I'd throw it out there.

While trying to come up with a way to have/generate multiple tempos in Realband I thought it would be nice if the program could have musical tempo layers or filters just as Photoshop has image layer effects or filters.

It seems that having individual tracks and mixer FX is sort of the same thing as having separate layers so thought this might be possible?

If the tempos could be put on separate layers then each layer could be set to its own tempo and maybe moved around easily.

Each Tempo Layer would effect the notes below it.
You could move the tempos around so when all the layers were played you could hear how they would sound in different parts of the song.

This could also mean a song could have a myriad of different tempos.
However I realize that many Realtracks can only be manipulated so far before sounding bad but maybe it would work with MIDI.

Well, that's it in a nutshell.
Now where did I put my tin foil hat?