Not sure if you are still looking for Vegas info but if you are then here is a story that is NOT a tale of woe - if you do your homework, there are good times to be had but at a much higher price than Europe. For me, I just wanted to experience a couple of Americans for a change :-)
I have had 3 separate girls off Eros Las Vegas (
http://www.eros.com/nevada/las_vegas/eros.htm) - 2 of them I've had twice - every one was exactly what I wanted but each time I paid for 2 hours, knowing that the girls will give good service for this. Prices for the 2 hours were between $500 and $600 - like I said - way more than you would ever consider spending in an FKK!
I've also had 2 girls off Naughty Reviews (
http://www.naughtyreviews.com/usa/nv/las-vegas?filters=ss_cck_field_basic_info_gender%3A1%20im_cck_field_looking_for%3A1) - same experience and same price range.
Each time I had a short list, I would cross check with The Erotic review (I'm in a hotel at the minute and for some reason that site is banned so I can't post the link but you can google it) and also on USA Sex guide
http://usasexguide.info/forum/ to look for reviews from other punters. Failing that I'd just google the girls and see if any unknown boards mentioned them.
I must warn you though that the professional girls that advertise on these boards are all paranoid about being caught by cops - so they do their homework on you. They will ask for your real name and hotel room number. They will then put down the phone and phone you back at the hotel. Some have asked for company I was working for and one checked me out on the web before she accepted the booking. Once you've been vetted by one and had a good experience, they will offer to be a reference for other providers - I've done this and it works great. Since I tend to go for the same "type" of girl, the 3 from Eros all happened to know eachother so references were passed on and I didn't need to go through the same process each time.
I didn't think I'd do it again after the first time due to the cost but for the last three times I've had the girls come to my room at 8am - which is a great way to work off that morning wood and not something I've been able to get anywhere else in the world so far :-)
If I was young and good looking, I'd agree with the previous poster - find an amateur - the girls on tour seem to be crying out for it over there and they write it off to that "what happens in Vegas" type thing.
Let us know how you fare when you get back.