With thanks to several Las Vegas hounds for their advice and input, recently I visited LV and tried Le Thai and Lotus of Siam. Both were excellent and I'd highly recommend either for someone looking (as I was) for something other than a meal in a fancy-named place on the Strip.
Le Thai is a tiny place - about 6-7 tables indoors with maybe twice as many on the patio. It's in a highly touristy area so that's not really my thing, but it didn't detract too much from the atmosphere. The food was outstanding; I had the three-color curry which was very flavorful, very very spicy, and very generously portioned. Earlier reviews indicated that service might be spotty; in fact, it was quick and helpful - and I was there at prime time on a weekend night.
Lotus of Siam is in a lower-rent neighborhood strip mall but the restaurant itself is bustling, welcoming, and nicely appointed (not fancy - just not low-rent like the rest of the strip mall). I tried the pad thai (among the best I've ever had outside Thailand) and the scallops with basil (also very good).
I'd happily return to either and LV hounds were right: there's a fantastic subculture of excellent Thai food here. What a great find! And thanks again to the locals who helped me with tips.