I hope someone can find this useful:
I bought one of the plastic top/bottom containers that hold 72 of the expandable jiffy type pellets. That is really the only thing I bought. The rest are things I had laying around the house.
I used a rubbermaid container top as the base (about 24x36). Then I used pieces of scrap wood (pieces of 4X4 posts I had left over from building a fence). You could also use empty tin cans or pretty much anything that can support 2-3 pounds. Put the 2 pieces of wood/whatever on the container lid. Put another container lid (same size) on top of the 2 pieces. In between the 2 pieces, put a strand of Christmas lights (this will bottom heat the plants). Plug them in. Put the plastic containers with the peat pots on top of the contraption. It should look like this:
()()()()()()()()()
____________
IxxxxxxxxxxI
_____________
() -
seeds in pots
_ - Lid top
I - Wood/whatever
X - Christmas lights
I hope that makes sense.