...to buffer many sensor lights with varing voltage trip points (and
scales).

For example, a thermocouple may only differ by a few millivolts from
"cold"
to trip point. Therefore it is necessary to expand the sensitivity
"window"
to a couple volts.
JZ

If you want better help, stop asking how you can do something
when you've *already figured it all out except the details*.
1) Give a better idea of *exactly* what you're trying to do.
2) Give some specifications--temperature range as a minumum.

Having said that, thermocouples are probably a terrible way to do
this.
(You're already aware of one big problem.)
Here's another:
http://www.google.com/search?&q=ther...ment+reference

Look into thermisters.