As to the transistor dummy load, keep in mind that the Hfe (the amplification factor) of a transistor raises when the temperature goes up.
Well, that rained on my parade a bit (as well as embarrassed me for not remembering it myself)! While the basic control circuit would be pretty simple (a negative feedback loop), getting it to track ten separate modules correctly and fairly accurately would be a horse of a different color, I suspect, and using a separate feedback loop for each module would increase the parts count and construction time prohibitively. Which leads me back to the original proposal of using resistance wire (of SOME type) as the load element.
As I originally noted, the two types of resistance wire I have considered are Constantan or Manganin. Problem is, I know very little about them and the help I've found on the internet is very limited. Can anyone lead me in the right direction as far as information on these materials goes or suggestions for alternative materials? All help is welcome and appreciated.