lift a feature from gnucleus:
 

"Drop uploads transferring at less than X kilobytes a second."

It always infuriates me to check on LimeWire, and find an enormous upload queue, with all the active uploads being BearShare users at 0.1 k/second.

These lamers should be autocancelled. If you can't download at at least 1 k/second, you should be offline, or browsing webpages, or anywhere but gnutella.

And why is it ALWAYS BearShare users? Is it some kind of plot against LimeWire users?

I have found that for some reason who connects to you seems to have allot to do with what port you are listening on. If I am on 6346 I get more LimeWire than other apps if it is listening on other ports the results vary depending on port. If you are running with UPnP enabled through a router the ports change regularly so you will notice this. I do not know if the port actually has anything to do with it or not it is just an observation.

I do think it is a good idea LimeWire should boot them if they sit at less than 1KB/s transfer rate for 70% of the time over say a 5 min. period of time.

i've found a workaround.
 

Go into preferences>uploads>slots

Set your max upload slots to about eight times as many as you think you'll need.

This way, it can keep opening slots until your specified bandwidth is reached.

Works pretty good, but it makes LimeWire take a LOT more cpu/memory.

I really think my suggestion would work better, but then again, I'm a little biased. ;)