I don't know if anyone has suggested this yet (or if there is a way to do this that I haven't found, or if it is going to be a feature in 4 , which I can't wait for) but I think that it would be cool if there were a way to switch between sets while live was running with out stopping.
basically to load a second live set that was synced to the first (or both to an external seqencer) it would load while the first was still running. once it loaded you could play tracks from the first set or the second (still with only one file per track (across both sets) but effects would be unique for each track per set) then when you were done with the first set you could close it and would play that set untill you wanted to load another set.
I hope this made sence.
currentlly I use live as a sampler synched to an external hardware sequencer. when performing live I have the samples from songs I want to perform in seperate folders and try to remember what effects I want to be on each. before the next song starts I drop the wav files from the upcoming song into the tracks and slowly delete the waves from the current song trying to drop new wavs into tracks with the correct effects. or switching while the track is unused.
next file
As for now...
for now... you cannot have multiple sets open... however, you can make one mega hoo hoo beast of a set and run from there 