With all that welding, what are you doing to ensure the frame is staying straight? I fear that you have created a MONSTER when it comes time to bolt the body/suspension on. Laying the frame on plastic boxes will allow the frame to REALLY move as you weld it. That's why chassis shops have big HEAVY steel tables when they build/weld chassis. If you secure the chassis to the floor, and have plumb bob points marked on the floor, you can verify the movement of the chassis as you weld. A long weld will pull an AMAZING amount. Do you have any measurements/plumb points before and after to use? You can weld beads and rapid cool to pull the frame back into alignment. Long welds should really be stich welded. I've heard of guys completely ruining a chassis by doing all the final welds (after tacking it together) on an uneven surface. A frame shop could pull it back into alignment, maybe. (but they would NEED pull points, aka holes.)
It does look really nice, though.
Not trying to rain on your parade, just giving you a heads-up.