Are you planning on building it yourself? Contracting a local builder? Or ordering from a retailer?
I'll be ordering my first rack in a month or so from a local builder I've met at reptile shows. Gonna be white melamine with notched shelves(SUPER STRONG), a single stack of (6) 32qt tubs with 4" THG heat tape(belly heat), no lids, room to add a front door if needed(to keep up cool side/ambient temps), and casters on the bottom for easy moving. I'm considering adding a locking system for each tub too. I plan on housing 2 males and 4 females. A perfect "start" to my collection. My snakes are a little small for a 32 qts right now, but they'll grow into them. I want my females to grow big, but I dread having to jump up to 41qt tubs. Those are HUGE!