Slab Storage Rack - Design and (http://maplered.com) Build my own?

I am considering having a local welding shop fabricate some slab storage racks (using the rail and (http://maplered.com) post design) rather than purchase them complete.
Any advice on if this a bad idea (unsafe, not cost effective, etc)?

I am thinking of a design that would store the Slabs (http://www.VerdeUbatuba.com) individually between posts (or leave a few post holes empty to stack multiple Slabs (http://www.VerdeUbatuba.com) ) and (http://maplered.com) have just enough space for an Abaco 50 lifter (2" posts on 6" center-to-center should work) to access each slab.
Does anyone have a design they would like to share?