Andrew,

I found plans for a solar wax melter at Barry Birkey's web site.
www.birkey.com/blb/beekeeping/index.html

You will also find plans there for building hive bodies, observation
hives and an extractor.

I built an insulated solar wax melter for about eight dollars two weeks
ago and it works very well.  I modified the dimensions on mine to permit
3 deep frames or 1 queen excluder to be placed inside.

Best of luck on your project.

Chuck McMarrow