And it takes Pentax lenses with an adapter...
The NONS SL660 is an EF-mount interchangeable lens camera that uses Fujifilm Instax Square Film: Digital Photography Review
For those not interested in the link to the "other" site, it's a kickstarter for a medium format SLR that takes Fuji Instax Square film.
It has a Canon EF lens mount natively, with lenses built in the camera to allow coverage of the film (best results with 28-60-ish mm lenses).
It can be used with other mount lenses via adapters - I'm not sure how those adapters handle differences in registration distance.
Pre-order pricing is ~$500, which is probably $100 less than "regular" price (whatever that means in Kickstarter-world).
That's a wildly specialist thing, and I don't want one, but it is interesting...
-Eric