@CJam: <$d000 is a restriction only for the final linked & crunched program. Once unpacked, an intro should not touch any RAM from end of intro to $ffff, to allow larger programs. The more RAM an intro clutters, the shorter a linked cracked game can be.
Also I don't understand what you mean with "that can be loaded with any fastload", an intro shouldn't load anything with any fastload, everything must be in memory, else there wouldn't be any memory restrictions =)
Ah, but how do you replace the bitsalad with a different bitsalad while still maintaining the old school workflow of the payload getting crunched along with the intro?
I am once again forced to conclude that Groepaz Is Right - compo should just specify a nominal payload, and everyone gets to use the same one.
Under Groepaz' proposal, my understanding is the payload may be compressed alongside the demo by the entrant (eg as per the workflow that Oswald described) - that makes it harder to replace, no? Particularly as the decompression might not be complete at the time the intro starts.