Hi piggywings,
If you decide to order the mattress before you move then the better options or possibilities I’m aware of in the Cleveland area (subject to the “quality/value” guidelines here) are listed in post #2 here. I believe that Original Mattress Factory will make custom sizes and it would probably also be worth checking with some of the Amish manufacturers in Sugarcreek and Apple Creek who would probably make them as well (but I would confirm this).
If you decide to wait until after you move then the list for the San Bernardino area in in post #7 here but I would call the manufacturers on the list that have mattresses that interest you before you move (both the factory directs and the local wholesale manufacturers) to confirm which of them can make a grand king just so you don’t end up waiting until after the move and then find out that none of them would make it.
I’m a side/back sleeper so I’m OK on my side because my knees are bent but my feet do hang over the end a little if I sleep on my back on almost any mattress (except a cal king). It’s just one of those things that you get used to … but I can only imagine what he must go through when you stay at a hotel that doesn’t have a cal king or stay at a friends home!
I met someone that was 7’ 2" at a store a while ago and at first glance I thought he was standing on a platform but then I realized how tall he was and being 8" taller than me I got a rare taste of how it feels to be standing beside someone that is much taller … it was very strange!
Phoenix