As you say, they made a ton of these guitars so there's always used parts on ebay or guys that specialize is stocking replacement parts by buying the trems and breaking them down. There's no real need for aftermarket, though there was a guy machining the T blocks you never see him post them on ebay anymore because there's always complete trems on there, and nuts, etc.
The parts of Ibanez guitars seem to be hit and miss on eBay. You should find people who machine parts and get into business with them.
You are the most visible Ibanez guy out there that I know of besides the big box stores and youtube presences.
Maybe you should get a long list of these guys on your site who have the old used parts (or machine them) but then in exchange get a percentage of their sales
It could help you some but help them a ton. I just don't know how any individual (probably hobbyist) guy can get exposure to sell his vintage Ibanez parts.
Visibility is a huge thing.
I make graphics/art for skateboards and have a couple of pros and amateurs I have sponsored, but unless I am Pac Sun, Macy's, Zumiez, or Tillies, it's hard to get known. I could take the top ten skaters in the world and get boards out to them, but being that they are all primarily sponsored by big box stores and big skate shoe/clothing companies, there's just no way to get widely known.
My friend who did this only got so far with his independent skateboard art/skate-surf clothing art because he was invisible outside the local area, so now he makes designs and has to sell off to those higher profile entities. On one end it's good that he gets on average $2,500 dollars per design they purchase and has given him the independence to move out of mom's house and start his own life, but then it's hard for him to see that company make a ton of them and get all the money. What was once done at his house and sold as unique art (let's say silk screened t-shirt) are now made in huge factories overseas. He was an artist of unique designs but now he's one of many design contacts on a rolodex. But like many small entrepreneurs in certain fields, he had to work with the big boys to make a living.
I think the monopoly of big companies/sellers makes it so smaller entrepreneurs in certain fields (probably guitar parts and certainly skate/surf designs) have to go to a partner that is much bigger than them. It may be a better choice to be a small part of a big fish than a totally invisible small fish.