Absolutely. I'm pretty much only interested in developing for MSX1. But it probably will need a 128kB or 256kB rom, at least as it looks now.
With your words you've just made me a happy man ^___^. If you need some help, please ask: here you'll find lots of good musicmen and gfx artists willing to give a hand, you bet!.
Well, I must say that a MSX2 version would be cool too
, but I prefer the MSX1 by far