As for the bass drum, you mentioned it being 22x20? Not sure exactly why you'd want a 24x22, logically with that much room to bounce and move around you could risk damaging it or having parts come loose. With a saturn, that's not something you want to do! Anyway, a quick search showed you can get that size. Here are some of the makers i've noticed carrying them:
[Cases]
Protechtor
Nomad
SKB
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