I think what I'll do is get a storage bin from Walmart and convert it to a terrarium, at least while they're growing. That will at least give me time to find a larger aquarium and do a vertical conversion on it.
I suppose it wouldn't hurt to ask this, but how hard would it be to use a 90 gallon hexagon aquarium for a terrarium? I know its far larger than I need, but I only mention it because of an add for one that's for sale here in a local ad that I could probably get on the cheap.