I have been a long time fan of recumbent trikes but they really have not caught on very well... at least not around where I live. The last time I went by TTR bikes... where I bought a Catrike a few years ago... they didn't even have any recumbent trikes in the store... mostly just two wheeled recumbents.
I just ran across a website a few days ago about Electric Bikes. Lots of great info there for DIY electric conversion and just about anything else you might be interested in concerning electric bikes including one story about an electric trike built in North Carolina that won the Pikes Peaks hill climb for electric bikes. They blew away the previous record.