I have multiple IGH bikes. The Schlumpf + XRF-5 that are going on the Sputnik are currently in a 1988 Gios Compact frame. It will take a bit of work to fit them to the track frame, but it's doable. The setup is being done by Dan Burkhart, who frequents bikeforums and has a ton of experience converting and servicing IGH drivetrains.
I'll use that setup for training and will decide late next year how to set the bike up for the climb.