Navpod is another option for you. Their pods will fit Edson or their own pedestal guards. There are a lot of options for add-ons from both companies, such as single instrument pods that attach on an arm of their own that can be afixed to the tubing of the guard, vs. replacing the pod you have or vs. adding another multi-instrument pod above or below your existing unit.
FYI, I just purchased a Navpod 10"x13" pod which I will be mounting on an Edson angled 58" x 9.5" x 1 1/8" guard. I'm almost done with the installation. I liked Edson's hardware (e.g. 'feet', binnacle bracket, etc.) but I liked Navpods pod prices better. The combination works and looks good.