Attend the Amelia Island Concours d'Elegance at Amelia Island, FL (2d weekend in March each year Amelia Concours D'Elegance) and you can. Luxury brands are placed at the entrance to the Ritz-Carlton Hotel. Mercedes, BMW, Jaguar, Porsche each have several of their top models available for test drives on Friday and Saturday. This year Mercedes had about eight AMG models including an SLS. Rolls, Bentley, and Lamborghini were there this year too, but only had one of each. Mercedes and Porsche were having the most people drive their cars.
Some of us on the South Wales sheep chase last year got to sit in one at the Mercedes dealer in Swansea. Easy to bonk your head getting in and out... Definately a lot of car.. Saw the F1 safety car version at Singapore last year and it does not hang about.... R)
We had both an SLS and a SLR come through Mecum's Indianapolis auction this year. Good looking cars though I was only able to get into the SLS. The owners drove both cars, but I chatted with the guy who had the SLS for awhile and then later on drove his Audi R8 Spyder..super nice chap.
I had a go in one last year, really fabulous. Wonderful sound, not convinced about the gullwing, I'd have the roadster (just that I want a G63 first lolz). Our dealership has had to find somewhere else to test now because someone who lives on one of the roads complained about the 'hooligans in noisy suped up cars'.