Man, I feel for you BigBoard.
You you what I find strange? I noticed that Ride makes the Big Foot boot for really tall people with foot sizes 16-twenty something, but at the same time they don't have any extra large bindings to fit that boot, nor an extra wide and long board neither.
What's up with that?
If you want better boots in a larger size, try a pair of Burton boots. They have a "footprint reduction" thing, which gives the boot a shorter length than most other boots, by using less materials and keeping a closer fit to the liner. This apparently shrinks the length of the whole boot down a full size, or so I've heard.
I'm 6'4" and have size 13 feet, yet right now I'm wearing Ride boots in size 14 (Ride Anthem Boa). I have a larger size because when I first tried them on, the 13s were just a little bit smaller
but the 14 fit fine...too fine as it now turns out! After using them for a season, they've loosened up a bit and now I'm thinking "shit! I should have gone with my own exact size-13!"
Oh well. I'm OK with wearing them for another season but next year I'm getting a pair of ThirtyTwos in size 13, which would work better anyway because I have Union bindings which are designed around ThirtyTwo boots.
BigBoard, I wish you luck with finding a binding, boot or both that work better for ya.