Need Help with Species Ident.

[Bighead]

A couple days ago a guy came into my shop and said he needed to give away 250 gal. multi-species enclosure with 2 breeding giant day geckos (not sure which sp.), an adult water dragon, and an adult "pink spotted river dragon." He says it's 3 feet long- the same as the water dragon and they get along great. All I really remember about the description is that it's got a big (i think he said purple) dewlap. I know that doesn't narrow it down very much, but I thought I'd see if anybody had heard of them anyway. It's driving me crazy, I can't find anything on the internet by that name. I'm guessing it has some other common name, but I'm not sure and I don't have a latin name. Any of you have any ideas?
Thanks.

P.S. Please- no comments about the multi-species thing. I've seen them all and I am prepared to sperate any animals if need be.