If it's going to be limited to WHC TBR wins, then there could be a "Make Offer" section for interested buyers to inquire about past TBR wins. I probably won't be listing anything there, but I would consider reasonable offers on my WHC portfolio. I might also want to make an offer on a domain that I lost out on, but then later made a sale or two that bumped up my available budget.
WHC account holders would be able to opt-in or opt-out of receiving offers.
I bring this up because I really don't see a huge demand for yet-another-marketplace, especially one limited to only .CA at one registrar, and this "Make Offer" option could really open it up to more potential buyers, sales and profits for WHC.
My concerns about an aftermarket system like this is ensuring bidders are fully verified and aren't just fake-account tire kickers or scammers. Also, there needs to be a minimum amount for unsolicited offers, such as 2X-4X the original winning WHC bid price to dissuade tire kickers.
And as to the overall marketplace, what would the commission charges be? What happens if WHC gets scammed on a payment, are they obligated by TOS to take the financial hit (like GD does) or would they come after the original owner? Would it strictly be BIN or also include Make Offer, Make Offer +BIN, etc. formats?