Heather that's a good point about the Instax cameras. I've got a mini, which I find fun to use in a Holga sort of way: it's so limiting that it's challenging.
I doubt we're going to see more advanced Instax cameras from Fuji. Polaroid, in its heyday, had a big market: kids, amateurs, hobbyists, pro-sumers, and professionals. So they made cameras and film for all of those markets. Now the professional film market is dead, dead, dead. (By professional, I mean commercial photographers) So it's unlikely that we will see much in the way of pro-quality film cameras, especially instant, in the future. The pro-sumer market is pretty dead too. The photo enthusiast, the go-to guy in the family for pics at weddings and reunions, has got a Nikon D60.
It's the art student with the tattoos and weird haircut who's locked in his bedroom messing around with weird cameras and film. (Hey, that's me!) It's a market, but not a huge one.