Contrary to what other people have said, you CAN have BPs and Cornsnakes on the same rack. I do. I have a eight 28qt tub rack. All you have to do is buy one WITHOUT heat tape and wire it yourself. Then you can have two different heat tapes, one set to a 90* hotspot and one on an 85* hotspot for the corn. That's how mine is. I've got 4 corns and 2 BPs in my rack and I've had no issues. Because it's very expensive to buy a pre-made rack, you can build your own. Mine was made out of a Home Depot plastic shelving unit. It works great. If you do something like that, you can have a row or two of 28qt tubs (2 per row) for your corns and use 28qt tub for your BP until it outgrows it and then upgrade to a 41 qt. The nice thing about this shelving unit is that it can hold both 28qt AND 41 qt. Here's an image of my rack:
If you did want to purchase a premade rack, you can order one from a company called "Evolution Reptile" their racks are not assembled, but they do have free shipping and you can put it together on your own. They have several sizes. I would recommend the four 41qt tub rack. I'm going to be purchasing the five 41qt tub in the future.