Building one out of a Redbull Mini fridge. It's the super minature one, so I had to COMPLETELY gut it today. I had at least 4 to 5 hrs into the just the guy out today. I got the fridge for 60 bucks though! So as far as money is concerned, even tho the work has been lengthy, it will be totally worth the work. Cheap! And the ones that I have seen look awesome and work like a charm. Check out Craig's List if you are looking to get one and find a mini fridge!
BTW, here is the link to the directions on how to build this thing. Awesome directions.
http://www.strictlyballs.ca/incubator.htm
Will Post pics when I get er' done! Happy Breeding everyone!