Have you thought about a band brake? I'm sure you've seen one somewhere, they're used on epicyclic gears to actuate them, amongst other things. A steel band with brake lining material runs around a brake drum on the outside, one end of the band is fixed and the other is pulled to tighten the band against the drum. There must be a four or five inch brake drum in the breakers yard somewhere that you could turn the outside smooth to accept a band? The band itself would be quite simple to invent, riveting brake linings backwards on to the band. This would have a gradual release, unlike a "cog" system.
Just my two euro cents,
Matthew
Alot of older Jeeps came with a drum parking on the transfer case from the factory.I'm not sure what years,but I had a 71 cj5 that had one.Those didn't work well at all.You would be better off with a disk and pads rather than a drum,If you decided to go that route.Personally I like the idea of a positive engagement parking brake.There wouldn't be no chance of it slipping and your beloved rig rolling off into the sunset.It's not a good feeling to see your rig leaving without you,believe me I know.
