Personally I would recommend the sweater box or CB-70 rack from ReptileBasics. With the sweater box rack you can choose between back or belly Flexwatt(heat tape). I keep all my BPs in RB racks and they all seem happy/healthy(eat and shed in one piece)
If you have any questions about your ambient temperature being too low for the racks I would recommend calling Rich, the guy who runs ReptileBasics. He is extremely helpful and I am sure would give you an honest opinion on if his racks are right for you.
Here is a link to his rack FAQ: http://www.reptilebasics.com/rack-faq.html