You might want to join the "Tandem Bicycle" Facebook page and see if anyone on that group are near by. They have nearly 1,500 members and maybe someone is near by that has a bike you could try.
Another option would be a weekend trip to one of the Tandem Shops in the south. I couldn't tell how far you would be from Tandem Limited in Birmingham AL or House of Tandems in Spring, TX north of Houston would be from you. It looks like it would be a long drive but we did some driving when we first started out. I'm the total opposite of you being very long-legged. :-) The other thing you could do is call Co-Motion or Santana and see what shop they have in the dealer network that has bike in stock that you could try.
Having gone through a couple of bikes in our process, I'd hate to see you get a cheap bike and then put a lot of upgrades into it. If you buy a cheap tandem try it out and then just look at that cost as the test ride if you were to drive to one of the tandem shops with hotels it would probably cost similar to what one of the cheaper bikes on ebay would cost. It would just be a shame to throw a lot of upgrade dollar to the cheap bike. If all goes well you can then make a very informed purchase. We purchased a too small for me Canondale as our second tandem and then proceeded to spend several hundred dollars to try and make it fit. We then bought the correct size and sold the Canondale for what we paid for it. So if I'd just gone with what I knew in my heart we could have put those wasted dollars to the new bike instead. Best of luck I'm sure you will enjoy tandeming!