Im wondering if anyone has been successful with finding a retrofit fix (GM?) for the whole assembly. My LX's e brake assemblies (driver and passenger) are all rusted up... Thanks for any constructive input. 
Correct. However it ain't cheap to go that route. Plus it's a pain to do a complete overhaul. My 80 is far from stock so I'm looking for something with better performance and easier to maintain.You can still buy all the parts new from Toyota or in a kit from @NLXTACY The original e-brake system works well on every 80 i owned so don't see the value in replacing it with a 3rd party system.
You're are 100% correct... And great thinking. But ultimately, a separate system is still better IMO since things get pretty bashed up on trails.I want to say the old Oldsmobile Tornado calipers had a mechanical engagement on top of the hydraulic so it could be used as an E-brake.