I agree with the point that you should not do this with reptiles not yet established in the captive pet trade. You could try it with other species though. If you're dead set on getting something with them, get some Rhampholean brevicaudatus or Rhampholean spectrum or Rhampholean temporalis. For care and basic info on any species you're looking into, visit http://adcham.com/html/taxonomy/taxonomy-map.html
You'll also want to get CB specimins ONLY!! from a reputable breeder. No point killing everything because of parasites.
You could also put stick insects in there. Corosius morosus (spell?) or even the big E.T.'s You really could use any stick insect you wanted, I guess whatever you can find.
Mantellas are too small, they'll get eaten. I've heard of pygmy chameleons being kept with larger Dendrobates species, but I've only heard a few cases where people kept them with Uroplatus.
Day geckos might be too agressive, as well as most other geckos, tree frogs are generally 'seek-and-destroy' goal oriented; I don't keep tree frogs, but if you wanted to look into it, go ahead.
Good luck in your ventures, but remember to remain honorable in regards to the propogation of the rarer exotic species in the pet trade. If it doesn't work the first time, don't waste more lives.
-Brock