well - consider making kits that are only 8 pieces... let me explain:
basically, a 16 track percussion sewuencer is a shitload. A 16 piece kit - also a lot. In my set - I do not use my MD, rather, I use my Xbase which gives me only 4 pieces! Plus I dedicate 2 tracks of the monomachine so that is 6 pieces total. What I propose offers you 2 more than I ever use.
So, you can have slot 1 be for kick - and also slot 9, and then build 2 kits out of the same kit. Then have essentially 2 patterns on the same pattern, which can make for a hugely smooth transition using mutes - or even the global mutes in song mode.
Its just a thought, intended to make you take another look at hardware :-D