Actually, I have tested this and WoW is not very much of a bandwidth hog like most people think it is. Remember, you can play WoW on a 56k modem. Obviously you can do 5 and 10 accounts over the same DSL/Cable connection. Eventually, yes you do run out but mostly due to upload bandwidth - and that can (like most things) be worked around to a certain degree.

I have managed something like 30 accounts on a 1.5 meg upload DSL connection just to see how far it would go. Around 25 it started to lag and 32+ was unplayable. 1.5 meg is 1500 kbps theoretical or 26 56k modem connections. It is only about 150 KBps actual (factor in TCP/IP overhead, etc) but again, WoW doesn't need too much to be *playable*.