The growing family (now at 7) was quickly outgrowing our large egg. 3 years ago when I bought it, I almost went back and got the XL but had sticker shock and stuck with the XL, and for just our family it was fine, but any time we had company I was doing multiple rounds on the grill. I have finally accepted that we need the bigger egg, and the wife is convinced the cost is worth it after eating on the egg for 3 years. A buddy from work bought my large and the basic table I made for it. The wife also wanted a 'built in' look, she was tired of looking at all my grilling accessories on the deck in tupperware containers.
I used a local granite guy who had some remnants that fit the bill to keep costs down. I thought about poured concrete, granite tile, but in the end I barely had the time to build this, much less the tops. I have since put the egg on a table nest as well. First 5 hour rib smoke and I cracked the granite. It closed up when the egg cooled off, it's sealed with epoxy now. Lesson learned the hard way :(
I used AirStone from Lowes, glued to hardiboard over a pressure treated 2x4 frame wrapped in roofing felt.