I saw these Speakman Shower Heads at a Westin:

http://www.plumbersurplus.com/ProductList.aspx?ID=565

But they had two of them hooked to a splitter. Anyone know what that
splitter is called?

Google is your friend. Use it.
I just put shower splitter on the search line, and got it.
Here is one of many sites that cover Y-pipes and Splitters
http://www.showersplus.com/Products/...ries/index.htm