Michael's craft stores have different sized clear acrylic plastic boxes available. If non fit, you could have a custom box made of clear plastic or 1/8 in thin glass too.

If going with RETFs, please do read our care article Frog Forum - Red-Eyed Leaf Frog/Red Eyed Tree Frog Care - Agalychnis callidryas and do a full quarantine on the frogs before releasing them in your live vivarium. Last thing you want is for a problem to show up once frogs are in there. Good luck !