Hey John - Looks like we share the same insanity
Im trying to get these ideas out of my head too.
Im still trying to figure out the rear shock mount locations and so far, the best I can see looks like what you said - ATK style. I have a 13.2" lg shock, 2.7" travel, and gives ~ 2.57:1 ratio at the mounting points I picked. I'll post them soon.
Looking forward to your rear fuel cell - Nice posts