30A Male to two 15A Female Y Adapter - where is it...?

Yes, each outlet is rated 15 amps - but - you can't add the outlets together to come up to 30 amps.

Link: http://www.defender.com/product.jsp?path=-1|328|299260|319692&id=1563668

You're limited to 15 amps total. Call Marinco toll free 800.307.6702 and ask.

Additionally it has a twist lock type plug so it won't work with the 30 amp receptacle in an RV park.