The widebody is out - I'm adding an extra inch to the depth (as a few peeps have already raised concers about breathing room for the driver, I know its okay at standard depth but what the heck, I've got enough ply) and I want to seal the piezos in in a David Perry stylee, so there just isn't enough plywood left. Plus I think I'd make a right mess of glueing the melded array (and am really not into treble on my bass in anycase).
Alex, thanks for the tip - I've been researching these cabs for months now and had already picked up on the balance issue. Plan is to do a dry run, find the CoG (in both directions) and route out rebates for the handles. Am going for sprung side handles, secured with bolts and t-nuts at the vertical CoG as well as depth for the occasions when the cab needs to be a one handed carry.