Elvis' ghost popped around long enough to write the following to me off-list (without any capitals!!!!!!!):
"benotto frames from mexico were made by the garzas, jaime and raul. their company made the handmade benotto models that were identical to derosa in 90% of the details; dubois lugs, pointed ss caps, diamond c'stays, and the like. the son, raul, refined his skills while working for derosa, though briefly. i think he was there on behalf of the benotto enterprise. this all is early 70s lore. i know this because the father, jaime and i shared bs sessions with raul at successive ny bike shows through the middle 70s. what i know about this comes/came from them."
So the link between De Rosa and Benotto exists but is not what Pete's source told him.