There've only been two that I've seen and now here's another! They call it the Triple Twenty. It's got nothing to do with the drivetrain, but rather the wheel size. 3 20 inchers rather than a single 20" in the back with 16's in the front.
1) How and why I purchased my first recumbent trike. 2) Accessories I've added, prices, where I got them and my opinion about each of them. 3)Trips and experiences. 4) Record of my discoveries 5) Preparation for the Aids Life Cycle