actually there were some isle of saint-marie babys at the place when I bought my ambanja. This was in Canada so I'd expect the US has at least some crawling around.
as for la reunion, I'm pretty sure I remember reading on the euro/french forum tanalahy.com that they were introduced to that island by accident and that the ones that are there do not leave the island for exportation/pet trade. (not 100% sure but it was something along these lines)