just testing the waters: would there be any interest in a conversion bearing retainer that would allow you to use a GM hydraulic throwout bearing? Selection for GM bearings is much greater and they are more reasonable as well.

Yes, there is interest, but there are three retainer diameters, two bolt patterns and two shaft diameters.

Not all combos apply but there at least 8 different retainers out there for the A833 setup.

I think it should be doable if you make the retainers modular: two or three plates and two tubes (for 18 an 23 splines). Tubes could be press fit (and maybe secured by a set screw) or welded.

Or just make a sleeve to press onto the retainer.

That is exactly what I'm going to do first (sleeve). If this works as expected I'm thinking about having some retainers made as not everybody has the means to make/press on a sleeve.

Can you put up some pics? I would like to see more information. I will be using a hyd. throw out bearing eventually so I would like to learn more.