I was going to suggest the Pacifica as a good compromise too, Johnny.
Historically we've rented with Dollar, but we've switched to Alamo for the last two trips and we've been happy with the "choose your vehicle" element. Last January we had a Cadillac SRX. We'd booked a Luxury category and it was sitting in the bay when we got to the garage, so we took it. It's not a 4x4 as such, but it fits your "high up" requirement and it was a lovely vehicle.
http://www.cadillac.com/cadillacjsp/model/gallery.jsp?model=srx&year=2007
For August, we've decided to go with Hertz. We've never considered them before because they're offsite at MCO, but thanks to positive reviews from Obi and others, and an unbelievable rate (£345 for 2 weeks for either a Lincoln Navigator or a Cadillac Escalade) it really is a no-brainer.