well after getting no answers anywhere, i went to the web to see what aftermarket companies are making for the sequoia.
reese shows a type of hitch that bolts around the "vehicle impact bar."
Part Number: 44602 (Now Available)
Description: Professional Receiver
Finish: Black Powder Coat
Warranty: Limited Lifetime
Weight Carrying: 600/6000 lbs.(TW/GTW)
Weight Distributing: 1000/10,000 lbs.(TW/GTW)
Weight: 21 lbs.
Size: 12.75" L x 7.5" W x 10" H
Package Type: Box w/Label
PDF Installation Instructions
Years Make/Model/Style Install
Time
2008-2010 Toyota Sequoia 40
so i went outside and looked at my sequoia to see what this was. this impact bar is actually part of the frame, is looks like it is a rear crossmember for the frame. this whole piece is actually welded, not bolted to the frame. the reese system just bolts around this "bar."
the factory tow package has a receiver actually welded to this bar in multiple places. it looks very stout.
so with this setup, i still have no idea what "class" receiver this is, but if toyota says I can tow 9000 + lbs, i will