For a 'once in a lifetime' elk hunt I would probably look hard at New Mexico or Arizona, even Utah. For some reason lately the elk seem to be averaging bigger in htese areas. Your best bet would be a private ranch with limited game quotas.
I'm heading to WY next week on a private ranch hunt. My outfitter only drew 2 elk tags this year (me and my friend). Talking to him earlier this week he said we will each shoot a nice bull. (I hope) He takes terminally ill children out on those "Hunt of a Lifetime" hunts every year. He had a young boy that he said won't make it to Christmas out last week and got him a nice 6x6.
This outfitter is a nice, honest and ethical man. He also attends all the big outdoor shows in PA, MI, etc. If you get a chance, look him up. Bruce Ferri, Canyon Creek Outfitters, Ennis, MT