I think the odds are pretty good that the Bills are exploring these types of scenarios already, behind the scenes, if for no other reason than to help them do "market research" to see how much Peters is truly worth paying should they decide to keep him. You owe it to yourself not to enter high stakes negotiations in a vacuum without understanding the current market.
And I think he is worth a boatload on the open market. A young franchise Pro Bowl LT doesn't come on the open market very often and I don't think 3 or 4 first day picks are out of the question. The issue is not what he's worth to the Bills, but what he is worth to other teams - that is what drives the market.
If you are the Bills and find that the street FA you picked up a few years ago has turned into the golden ticket, you have to look at trading that for the chance to fill out your roster with quality at several positions.