Thanks for all the great responses ! I am constantly AMAZED at the breadth and depth of experience of the members here !
The baby-boom bulge in the population demographic (born 1946-64) means there is a significant portion of the population that forms the "pig-inside-the-python" bell-curve of old folks. They are bored and have some money, and are walking/biking for boredom and health. As soon as many of them try a recumbent, they want one, but the price is daunting (Wal-Mart recently began selling a cheap Chinese copy of a popular 'Bent http://endless-sphere.com/forums/viewtopic.php?f=3&t=10378&start=0
Most recumbents use fairly off-the-shelf (OTS) hard parts, and the only custom part is the odd-shaped frame. I myself bought a WM MTB because it was the cheapest way to get full-suspension, fat-tires, and a front disc brake. I immediately converted it to a semi-recumbent ("beach cruiser" style of seating) and I find myself drawn to custom-framed bikes to study alternative (affordable garage-made) building methods. No need for me to "re-invent the wheel".
I posted this thread and the "wooden bikes" thread as a result of alternative frame-building research I felt would be amusing to the E-bike community.
That being said, I feel compelled to emphasize the need for engineering. By that I mean, if you take your common aluminum soda/beer can, it can be easily collapsed by a thumb and forefinger closing in on its sides. But place 4 of them together on the floor and place a wooden square plank on their tops...such a configuration can support a 200-lb man if the weight is applied slowly and carefully.
So, I encourage any experimenters to make a project "too strong" and use each element to emphasize its strengths and avoid its weaknesses. Heliarc-ing thin-wall aluminum tubing would be expensive and time-consuming to learn, but I am now certain that I could make a custom recumbent E-frame based on the collected information you have all supplied me. For that, I am grateful ! and I hope this thread will prove useful to others...