Based off of the research I have done, most sequoia owners are going with the revtek spacers.
I think I would either go with a donahoe or swayaway coilovers in the front and a a custom spring in the rear. I might go with a spacer in the rear though. Depends on how it stuffed. You can fit a 32 inch tire with no lift. Or a 33 inch tire with a 2 inch lift. Watch your backspacing if you go go with a wider tire as they will rub on the upper A arms.
There were a few guys that put big lifts on them. Supposedly any late model tundra lift will work on the front of the sequoia, but I can't vouch for that personally. There is ony guy who installed an RCD lift on the front.