Treitz3, thanks for the welcome!
I had a look for you to see if there was an 'official' dimension for wall thickness and couldn't see it, however would guess at slightly under 1 inch, with insulation inside.
http://www.broilkingbbq.com/grills/keg/landing.html
Just joined the forum, thats my excuse for picking up this thread after a few months so please excuse me!
Based in Melbourne, Australia and use the Broil King Keg and find it to be absolutely incredible. Think Big Green Egg made out of metal and you are on the right track.