I've got access locally to all kinds of trinkets that could be used as bolt-bars etc such as stainless roundbar and other things. As far as an inner box goes, it's in the plan and was gonna use sheetrock between the two. Can't go the weight route because of the final location, doubt the floor would hold it, house is on peirs and thinkin' about puttin' it upstairs too.

What's that lil square halfway up the vertical piece that holds the boltbars in alignment? Is it a retainer to keep everything semi tight?