Bob,
If I was going to spend that kind of money on a transmission I would go with the liberty. The trick would be getting the clutch setup and the stick gears setup for a small tire car.
Even the best converter has some slippage on the top end. That is where you should be driving around the automatic car with a stick. Clutches are a lot more durable and reliable than a decade ago. This is why you are seeing more stick cars being built for the hemi shootouts.
If the rules state the stick cars can only have 4 gears that is alright. There are tricks to make that 4 speed run like a 5 speed!