There are a bevy of forums that impose INF minute edit restrictions. In light of that, 60 might as well be 0.
It is desirable to ensure that poorly thought out comments remain on the site forever, or at least until the next crash? Or perhaps the administrators derive some sort of pleasure from imposing yet another restriction on a forum that has a virtual monopoly over its subject area?
The solution is to create one thread for each one item you are selling. I foresee that this will soon be banned, however.
Another idea now that images may be embedded into posts is to create all of your posts as remotely-hosted transparent GIFs. Then you can edit them whenever you like.
I foresee transparent GIFs being banned for this purpose.