back in 2000 I was working part time in a camera shop. the owner of that shop had been collecting camera manuals for decades. He had been scanning them in high def - took him forever.
he finally retired, closed the shop, sold the building and moved to the Carolina's (SC I think) and then sat back and I believe has been selling PDF versions of every camera manual since then. The work has already been done (scanning in the manuals) and now all he has to do is pick which file for a requested manual and boom, off it goes
that might be an excellent business for HK manuals. All the manuals that they have made. Turn them into PDF's and offer them all.
I think he got like $9.99 for his - sent them all over the net to who ever wanted one. His goal was to sell one manual a day. Pretty good living if he ever did it. Could be the same for someone here.