I do not know of a website...but we have always had excellent luck bidding for a 3* hotel in the MCO area on Priceline. For a bid between $34 and $42 depending on when you are going you can get a very nice hotel.
All of Pricelines 3*'s in that area have complimentary shuttle service 24/7. They book at the Hyatt inside the airport, Holiday Inn Select, Marriott and Renaissance. Ocaasionally at the Crowne Plaza also. We have stayed at all of those via Priceline bids except the Crowne Plaza...much nicer than you would expect for that price.
After your bid is accepted and you find out which hotel, you can call the hotel directly and request a room with 2 beds (or king with sleeper sofa, or whatever). We have never had a problem getting exactly the room type requested in 10 or 12 stays at those hotels.
If you go lower than 3 stars not all of the hotels have shuttles, or some of them only run certain hours...not worth the 4 to 6 dollars you would save on a lower rated hotel.