you can go to the ceramic grill store and get an adjustable rig to give you 2 extra racks.
I have an XL egg and at times I feel I've outgrown it and need more real estate space (I have the Adj Rig for the XL egg).
Part of me has thought about getting an insulated vertical smoker, but for just back yard needs, I think I may just get another XL Egg. I already have all the toys needed (plate setter, woo and stone, adjustable rig, pizza stone, etc), so I can be making pizzas on one egg while smoking something on another, or can smoke on both eggs if needed. If its just for backyard cooking, I think 2 L or XL eggs is likely enough. If you are talking about the itch to compete, do catering, etc, you are likely better off looking at a Pitmaker or something along those lines.