If your getting into breeding or if you know you will be purchasing more snakes then I would suggest the herpstat 2 or the VE-300x2. They're both dual which will allow you to run two different racks or a rack and an incubator in the future.
If you want to build one out of melamine these are the dimensions of a 7 tub 28qrt sterlilte wide rack. You can use this rack for bps from 350g - 2000g
2 - 49" x 17"
8 - 23" x 17"
Then just use CDs for spacers