I don't know if this will work or not, but just an idea since nobody has posted anything yet. (I am assuming this would be to pull out of the basement and swivel it up to view it outside of the TT?)
I would think something like this - Amazon.com: 17" Extension Slide-Out Accessory for Furniture Swivel Mount: Electronics
With this attached to it - Amazon.com: VideoSecu Articulating TV Wall Mount for 22-37" VESA 200 100 LED LCD TV Monitor Full Motion Bracket 3V7: Electronics
and your TV attached to that might do the trick.
I've never attempted this, so results are unknown, but whatever you wind up doing, it's probably going to be a complete custom setup. I haven't ran into any accessories offering this functionality as of yet.
Good luck, post some photos once you come up with something...i think we'll all be interested in your mod.
Where we've been:
2000 Rockwood Roo M-18 Hybrid
2006 Dodge Ram 2500 Auto 5.9 Diesel
Gone but not forgotten -1986 Rockwood 1003 PUP