Scaphiophryne gottlebei is a beautiful frog, it is critically endangered in its native Madagascar, but I have seen it occasionally in the pet trade and quite expensive.

I have experience with Scaphiophryne marmorata and S. madagascariensis , when I worked at the local zoo as an amphibian keeper. These are very interesting frogs but their fossorial (burrowing) habits makes them a less than exciting terrarium creature. If you haven't had experience with Madagascar Rain (Burrowing) Frogs, I suggest getting S. madagascariensis, they seem to be the most active and visible of the frogs in this genus.