Here is one for sale on kingsnake, but with gas prices it could get expensive!

http://market.kingsnake.com/detail.php?cat=22&de=595234

Look around on there and you may find something closer!

I would offer to build one for you, but my time at home is limited and I have to build 2 more for us next time I am home. Our rat colonies are growing fast. Generally the walk throughs I've seen on line tend to assume some carpentry skills are known. Also a hand drill is needed as all screw holes need to be pilot drilled first.