Thanks to everyone that answered my questions and to everyone on this board that has shared ideas and knowledge. I've been working on my islands - one 12ft kitchen and one 12ft bar table with fire pit. For the bases, I used 20ga 3 5/8 steel from Calply and the bar countertop I used 20ga 2.5inch steel. I'm still working on the framing, but have most of it done. I plan on using Durock all over then then porcelain tile for the counter. The fire pit is 36" long and the parts for that should arrive tomorrow.
Here's the kitchen section that will hold my 6-burner Summit (shelves removed), smokey mountain, and Lion ice bin (not pictured) on the far end right. I will also be using the side burner from the summit (not pictured).
Here's the bar height island so far. The 36" long fire pit will be in the middle of the center section. I doubled up the beams all across the counter using a stud inside the track steel.
I hope to be able to get this completed by Easter.