Does this shop have an online presence? Are you sure they are Geosesarma sp. "Red" and not more common Tomato Crabs? I've been bombarded with requests for the red Geos on several forums, it'd be nice to be able to hand the people off to someone who has them for those who are too impatient to wait for mine to have babies. Some people really get all offended when you won't sell them some of your critters, it's really something!
Anyway, if the leaf tails you saw were twice the size of your hand I'm guessing they were
Uroplatus lineatus the largest species.
U. phantasticus is the smallest species maxing out at about 5" long, about perfect size for me but the sikorae would be alright too as they're only a couple inches longer. Both are amazing camouflage experts which is what I like.