Prindle 16, Hobie 16, Nacra 5.0 or 450--all good choices for a first cat. Sure, there's differences between them. The prindle, for example, has more freeboard to the hulls than the hobie. But just get the one that is most convenient for now. After a season sailing it, you could always sell it for what you paid for it and get something different.

Bear Lake is too rural to bother looking in a newpaper for cat listings (tractors, yes; catamarans, no). I you see a descent looking cat off in the weeds (and this goes for anywhere), go knock on the nearest door and find out who owns it and if they want to sell it. You should definitely be able to find a good deal on something much closer than Tennessee. It's just not necessary to go that far for these relatively common boats. California has a good reservoir of semi-abandoned catamarans and is a lot closer. Post on TheBeachcats.com list to see if anyone knows of a boat. I met a guy named Tom House up at Bear Lake this year. He follows that list. He's got a veritable armada of beach cats and may have one to sell you. He lives in SLC area but has a place at Bear Lake.