1,000 per month is the manufacturing capacity, according to the videos around the M9 launch.
Estimates are that 20-25% of those are allocated to the US. That's where Robert (Monza) came up with his numbers above - that would be about 200-250 M9's entering the US per month at full capacity.
After the first 20 that hit the first week, and a small trickle on the third week after launch, I have not heard of any other M9's getting to the US.
So either Leica is not yet manufacturing at full capacity, or allocations are going to other regions over the US.