Might as well add Bike Friday to the list, of Imports, Hank

Tikit offers a bunch of IGH options. season tikit offers a chain tensioner rear dropout,
with interchangable end fittings for a number of options.

I have one of their Travel bikes , it has the IGH option, frame fitting,
with a chain tensioner [R'off in my case, long left dropout slot
for internal torque stop]
Made in Oregon USA