Crutchfield and many other audio supply stores have been no help. So.
Last year I installed a double DIN stereo that takes a 32 pin plug. The radio happened to include a cut off harness already attached to the radio. I spliced it in to the 94 Roadmaster harness, got a 95-96 dash bezel, and the 95-96 mounting brackets to adapt the newer Stereo head in. It is working fine.
I found a full length GM T-harness for a Delco changer that physically allowed me to hook up the changer to the head unit. But it kept on blowing fuses. It turns out the seller found out this harness is defective as were the other 10+ harnesses he had. He returned them to GM. I also got my money back.
So, I have been trying to find a way to get a 12 CD changer in my 94 Roadmaster ever since. I found out about the part I pictured in the OP too late, as they are no longer available.
Sooooo, I took the OTHER GM harness (the one pictured above) and took out all the wire pins from the plastic connector and inserted them into the appropriate slots in the factory plug in the radio. Now it WORKS and I finally have a GM 12 CD changer in my 94 Roadmaster!