Yeah, this is a concern. The edges of the keggle actuall rest on the inside rails of the main beams. I have plans to add in some cross supports for it to rest on. I'm gonna get a brew on it and keep an eye on it to see how it holds up.
The top burner is mounted directly to the metal grate under the keggle. The bottom burner is sitting on a cradle made from banding strap that is bolted to the inside of the shelves. That way I can lift it out if I want to use it separately from the brew stand.
I'm in Indy.. over by the airport. GF is where I get all of my brewing supplies. Great place, great people. Grew up in the region. Every time i'm home I try to get to 3 floyds... I just wish they had Zombie Dust more often.. might be my favorite beer of all time!