Yes, there should be. And although I'm not sure if there are rules 'formally', but I have noticed the DM's on shout a few times the last couple of weeks telling players not to drop their stuff on the ground and leave it.
On at least three or four occasions DM's have come on 'shout' and reminded players that there are reasons why they have trash-cans and drop-boxes around.
In addition, (you probably already know this) but when you kill a critter, and want to get rid of some gear, click on the 'remains' and drop your un-wanted gear in it. When the clean-up script runs after you leave the area, it will get rid of your unwanted gear as well, and its easier on the server than just dropping it on the ground, and letting the clean-up scripts work that way. The scripts work more efficiently if it sees your gear as 'remains' and not a piece of material (coding) on the ground with all its attributes, etc.
There are several add-ons you can get they are called in general 'hak-paks'. A whole bunch as a matter of fact. You can spend all day downloading and installing them. To me they are something of a waste of time if other people cant see them without downloading the pack themselves. In addition Leto is a neat little program if you find a server that supports it. What I mean by that is that some servers will *see* a character created by leto as an *illegal* character and keep you from logging on. So I just don't mess with it anymore.
For some nice looking portraits go here;
http://nwvault.ign.com/View.php?view=Portraits.List
for hack-packs and such go here;
http://nwvault.ign.com/View.php?view=La ... ays_back=1
Be careful though, some of these can gimp your system, and im not sure what they will do to you current file arrangement. One of the things that they tend to screw up is the 'Update' function on your installation. This happened to me this last update, and I had to use a 'critical file rebuild' which eliminated all of the hack-packs and add-ons I had in place. So now I don't even bother.
I hope this helps.