The hotels you mention, Marina, Elephant and Two Guys are NOT upscale hotels.

I believe that Mosaic in Day - Night Plaza does not check IDs but most other places do.

In vicinity of Boyztown there is Avani which is upscale @ 3000 Baht/night.Very nice but IDs will be checked.

If in Jomtien you can do a bit of research either here or on gaythailand.com forum for some good hotel choices.