@redsquirrel
I haven't seen any other forums that allow a user to lock their own threads. It could be nice from a moderation stand point, but I think it could create some other problems. I'm perfectly happy editing the title and waiting for a Mod to lock. I'm also in favor of requiring sellers to leave the original info/price in the post for others to reference. The "market is going to market" with or without that info, but having it makes things easier.
What I would really like to see is a buyer/seller feedback system. For example, I think the format/functionality used on AR15.com works very well. It doesn't require Mod involvement and is attached to the users profile. So, in addition to joined date, messages, and location; there could be a number of "positive" and "negative" ratings. You could easily see how many good and bad transactions a member has.
Screenshot example, user has a 100% positive feedback with over 300 transactions.
View attachment 30222
For what it's worth, I've only had one bad experience in the classified here and I'd consider it a minor one.