i think it would be interesting to see the buy sell forums updated to something like what pinkbike (kinda the mtb version ns) has. i personally find it hard to find what you're looking for without searching through a lot of forums and a lot of dms. the way pinkbike does it is though many filters such as location, specific categories (potentially on ns skis, boots, jackets, pants), price, weather they will ship locally internationally or not at all, price, open to trades etc.
i realize that making the buy/sell section of pinkbike probably costs waaaay more and takes many more hours than ns might be willing to invest in this but i think even a very basic version of that would help a ton with b/s/t
i don't know how many nsers are also on pinkbike but for those who aren't check it out here, mess around with the filters and what not, let me know your thoughts on this.
http://www.pinkbike.com/buysell/