I took a few minutes and did some searching on the Internet this morning. Learned a little about building a cheap hot tub. It seems my origional idea was basically sound. A lot of people have already done exactly what I had planned with variations of course.
Anyway my basic idea was doable!
It's really strange to come up with ideas on how to do something and find that someone else has been there done that. Even more so when the idea is sound. My idea incorporates both wood heating and solar heating which would be a little more efficient. Neither system needs electricity. A lot of people have used a Rubbermaid horse trough in thier design. I'm, planning on a galvanized trough with a thin coat of truck bed liner sprayed into it which should be a little more ridged and afford freestanding on feet.