Sheraton Vistana Villages is a resort of serviced 1 and 2 bed apartments within walking distance of a supermarket on I-Drive. You can get the trolley to Universal and shuttle buses to Disney.
We stayed there last year but did actually rent a car which was brilliant.
While not a villa, it is one way to keep costs down while keeping some freedom (ie having a kitchen and washer/dryer) and is very luxurious.