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

I think this is what you are looking for:

http://www.amazon.com/Conntek-3-Feet-Adapter-Connector-Indicator/dp/B007ZTAE5A



same thing:

http://cordtec.com/products.asp?id=744



It is rated 3,750 watts so two 15 amp outlets (not circuits).

I'm a little surprised it exists because, without any 15 amp circuit breaker protection, you could easily overload a 15 amp extension cord.

It is safe enough though if used correctly.