Recently, I was in the same quandry except I was renting a SUV instead of a luxury car and I was renting from TPA instead of FLL.
When I found the SUV area there were only fake SUVs, Buick Rendezvous and Chevy Equinox (Equini??). I did confirm that I was in the Standard SUV area not the mid-size area which was father down the row. After walking around a bit, I found the EA/Exec Aisle and sitting there smack dab in the EA was a Yukon Denali with 6 miles on it. Totally confused, I asked the attendant and he said that nobody wants them since gas went crazy and they were putting their larger SUVs in the EA/Exec Aisle. I got into the Yukon, started up my laptop, punched up my res for a SUV and modified it for a mid-size car. I took the Yukon saved $200 and I am still unsure why National would not ensure that a SUV was in the SUV aisle when somebody made a reservation for one.
Dan