Actually, this may be something we (and by we, I probably mean "I") want to do. I can see it as an additional incentive to advertisers, and I've had more than one person tell me that they're interested in seeing a hyperlinked list of folks who have advertised on the site before. I wanted this myself, when I wanted to buy Redhurst: Academy of Magic but couldn't remember who published it.
The smart thing, of course, would be to start doing it with the current advertisers and not the previous ones. Link the page to the Main Page, and just have it around for when people need it for reference.