You can go to hd, lowes ,menards, & buy 4x8 sheets of 1/2" or 3/4" melamine for under $40 a sheet & cut to size. The heat tape is like $2.10 per foot. & you can have it sent pre wired. You can use a single zone thermostat like herpstat 1.
I would never buy a rack from a company it just seems like a ton of money to spend on something I could make myself. But then again I work in a factory that makes office furniture so I have access to free scrap melamine & all the equipment.