Has anyone ever considered taking, say, a $5 stuffed hairy gorilla toy, cutting it open, and using the "hair" to make Optimus Primal more "real" looking?

I'm kinda considering this, with my Air Attack Optimus Primal. Do you think I should cut chunks of "molded fur" plastic away, so that the hair can be flush with the techno parts, or will laying the fur on top look alright?

 

I've thought about it, but not to the extent of actually wanting to do it myself. You (or someone here) needs to do this  

 

while I don't have an air attack primal, I would think about doing this to either the original or anniversary version of the original BW mold Optimus Primal. I would probably sand the molded fur down a bit to compensate for the thickness of the material the fake fur is stitched onto.

 

I like the idea, but I imagine the hairs could be too long and thick for that scale of model. I found this flocking tutorial that might be of value to you, I think it would do a better job of simulating short fur.

Flocking Tutorial