How many of you accidentally vendored something of worth? I bet alot. What I suggest is very similar to the WoW buy-back system, if you vendor something you can buy it back until you have logged out, then its really gone. It would save so many good items ^_^ (rip my nicely scrolled maple lama staff, you will be missed.)
Cant remember why. But i remeber something about too much command will ruin the server. Try searching the forum
I think it was not coded in new source and has yet to be recoded. Just like many of the commands we had in old source but do not have currently.