Reunion Resort has lots of very elegant homes from condos to 8 br pool homes.
They don't have much in the way of theme bedrooms but there are some fantastic homes there.
Windsor Hills is another of the newest with pool homes and there are some nice ones there. You can find them on windsorhillsrent.com or vrbo or homeaway for Kissimmee. The storytime homes in WH have great theme bedrooms:
http://storytimeorlandorental.com/ but there are also many more. We stayed in this one
http://www.homeaway.com/vacation-rental/p250801
But don't count out the other subdivisions either. Many homes have been bought in the last year or two and have been completely upgraded and redecorated.
How big do you need? There are 7 bedroom homes in Formosa Gardens Estates that are fabulous.
http://www.star-lake-manor.co.uk/
We stayed in this 7 br in Emerald Island :
http://www.homeaway.com/vacation-rental/p253707
You've got to basically go through the listings. Allstarvacationhomes have lots of nice ones also. I find they are more expensive than renting directly from the owner.