Some registrars do offer this in one form or another and I believe WHC has stated it's in the works...
That said, domainers selling their excess stock is never going to hit the same price level as TBR domains. Buyers just view them differently, as an "investor auction" will always look like a loser domain they couldn't sell with all its potential wrung out of it, and right or wrong, expired TBR domains just have that fresh, unknown quality that just gleams with untapped potential, leading to mass overbidding in a lot of cases.
This phenomenon is well-known in the current Expired Domain auctions, as stuff people wouldn't pay $50 for on NP suddenly erupts and sells for thousands at GD expired auction. Apples and oranges.