I'm a big fan of Jake Wildwood's stuff and he's got a great reputation. He had a 1925 Oscar Schmidt Tiple up for sale a few months ago. You can email him and tell him what you're looking for and he might have something for you if not now, in the future.
I've owned 5 or 6 tiples. Gretsch, Martins and Yasuma were decent. Regal was just ok. In my opinion, the Martins are the best. Keep an eye out for a T-15 or T-17, I had a sweet one that I bought cheap. But whatever you decide on, make sure the neck is straight, the bridge is secure and it's always helpful to play it if you can. You won't have to buy tiple strings either, do a little research, determine the gauge strings you want for each course and buy single strings of your favorite brand from www.juststrings.com.