This is all terrific guys, thanks for the feedback.
As if the choice of table weren't fraught enough, the choice of BGE model is now the focus!! We have large gatherings (20-30 people) about 4 times a year, so the XL size seems to be the one to go for, but the conventional wisdom is a Large, then a small. I just can't see an 18" being large enough for the big cookouts. So it looks like an XL, although I'm worried about regulating the beast's temperature, and then there's the fuel consumption. Which suggests a large and a small. But then the wife doesn't want two grills.
On the woodworking front, obviously the choice of grills influences the design. What I'm thinking right now is to make the damn thing out of PT softwood, knowing I'm going to change it in a year or so, and then make the final job out of white oak.
But thanks again for the help & advice, this is truly a nice problem to have. If frustrating!