I asked Jennifer Whitehair, the senior online editor for the popular tourist site Vegas.com (owned by the same parent company as Las Vegas Weekly, where I am on staff), how to get a late night massage in Las Vegas that is a legitimate massage. Here is her answer:

 

"Many hotel spas (For example The Spa at Wynn Las Vegas) offer in-room massages. You can call the hotel spa directly using your room phone or any house phone. You can also call the hotel's concierge desk. The concierge can help you make reservations. However, most hotel spa facilities close between 7 p.m. and 8 p.m. at night. For an in-room, after hours massage or other spa service, contact your hotel concierge. The concierge will know if the hotel spa offers after hours services. They can also tell you if the hotel has contracted with any other Las Vegas company to provide in-room massages and spa services."

 

This and other conversations today have led me to think that in Las Vegas you would generally do best to check with a hotel concierge or spa rather than asking a taxi or limo driver where to go; that is, if you are looking for a massage that is meant only to be a professional massage.