I believe some of you have considered it before, but has anyone gone ahead and housed any hyperoliid reed frogs in a riparium? This is a very diverse family of small tree frogs found in the mainland Afrotropics and Madagascar, and it seems like they'd do great (with targeted feeding of small crickets or fruit flies) in a closed-top riparium with a combination of tall sedges like Cyperus
and broader leaved plants like Anubias
A lot of the herp boards seem to be hugely wary of drowning potential, but I'm wondering now whether that risk isn't very much overblown. I mean, many Hyperolius
in particular are closely associated with lily pads and other floating pond vegetation, papyrus swamps, and the like (the "tree" can be something of a misnomer). I've heard it reported that most of these guys will actually dive into water when startled and remain on the bottom of their own volition until the threat passes -- which shouldn't be problematic in tanks without very strong flow ... or large, predatory fish.
Examples of reed frogs in paludaria with extensive water features here