Your search answered your question, if there was a quick and easy disk brake lsd rear end for a TA22/RA23/28....we would all be talking and raving about it. As it is, there is not, so we cobble together combinations of bits to give us what we need.
Besides, when I went through this exercise I spoke to two diff mod shops in Perth and they both said that they could cut down any Commodore rear axle to any size and make that fit, using the original axle as a model.
So, maybe a cut down Commodore rear end is the answer you need to match your Commodore motor.
Might be cheaper to make a two door chopped top 89 VN in the end !