I visited Madagascar a couple of years ago for two weeks, and visited the south of the island. Saw a dozen lemur species, tenrec, boa, numerous chameleon species, giraffe-necked weevil, humpback whale, and members of all the endemic bird families. There is a full write up on Bird Forum; search for A mad month in Madagascar. It was organised directly through a ground agent, Gaby, and as a result was MUCH cheaper than the usual tours. However, be aware that road travel is exceptionally slow, so we lost more than two days doing nothing but travelling. The wildlife is localised, but the local guides (compulsory in various sites) really know their stuff, but make sure you specify everything you would like to see; we almost missed some easy to see owls because we had headed off to see Abert’s Tetraka, and the guides did not think to mention the possibility of the owls.