Went to the NRA convention yesterday, 4/10/15, just for the vendors. The Glock display was stacked with lookers and gawkers all wanting to get their hands on the single-stack 9mm M43. When I got my turn at it I found it is extremely close in size to the 380 M42, only very slightly larger. Trim, thin, and light, meant to be carried a lot and shot a little. Magazine capacity is 6 rounds. The grip area is really thin, would have preferred a thicker feel for more control in the hand but they opted for a flat profile to reduce "printing" under a shirt, etc.
It seems that everyone wants a 3.5 trigger connector in their Glock. I asked about the trigger connector in this model and learned that it is NOT inter-changeable with the M17, M19 etc. connector. This one is it's own unique size and nothing else (for now) will replace it. Same story with the M42 (380) connector. Perhaps the after-market vendors will step up to the plate on this soon.
As for availability, the factory rep advised "we started shipping them out today."