This should be done via the Auction Hall. The AH already supports WTS (Want To Sell) orders. It could be extended to WTB (Want To Buy) orders. The problem is convincing Turbine to extend the AH functionality. The last time a Turbine employee talked about the AH it was stated that the AH is a finished feature only very minor changes will be done going forward. A number of the game features belong to the "finished" category. No enhancements are going to be done.
The 2013 feature of the year is a housing update. Maybe kinship support will be the 2014 feature of the year.
Unless stated otherwise, all content in this post is My Personal Opinion.