I've rented a jeep wrangler from Fox car rental. They're off site on N Temple, but have a shuttle from the airport. I think they only have 2 door models though, and the one I rented had really been put through its paces. Soft top windows were so scratched up I could barely see through them. But for what u want, it may be a good option. Price generally runs between $300 to $500 per week.
Now I have seen JKUs in the airport rental lot from the major rental car companies (specifically Hertz). You may need to call and specify you want reserve a wrangler.