Pretty much any rental car company offers luxury car rental. You just have to specify what you want.
I know Enterprise rents luxury cars, so you can just check with them.
I'm not sure about any of the other places.
Almost all car rental companies have a "luxury" category. Some even have "prestige" or specialty categories. There are companies, like Priority One Auto Rental in Boston,MA that only do luxury car service nyc. Usually you can get a better selection of cars, and much better service, by going to a company that specializes in this area.
