Bringing this back because I found a another unicorn.
I recently found a thread on tuners about a Japanese built adjustable clutch plate coupler that replaces the stock VCU. The description seems to suggest that it does pretty much the same as the Ralliart VCU except that the plates inside the housing can be adjusted so that the user can change how much torque is sent to the rear.
Apparently they were discontinued a while back but a contact of mine somehow talked them into to reproducing one for me but on the proviso that I make a decision to move on it quickly. It's not cheap (120,000 yen) but with Ralliart gone or on the way out, this may be the last thing available to do what I want. Apparently this came out of an EVO III transmission. Does anyone know if there is any difference between our couplers and those used in early EVO units?