For the new route maybe implement instaban with longer durations for each violation. I.E. bumps, GLWS, i want this, etc. would be instabans that eventually lead to permanent bans. To enforce this rule further, mods could go in and delete unnecessary posts.

I say keep the thread open for posts to ask questions about item being sold. This way people are kept informed real time and the OP doesn't need to update thread constantly, except for marking "SOLD" etc. Increasing PM box to 300 would be nice too.