AbigailII: I agree with you, how many games I have going does not affect how fast I play. Because I'm on the west coast of the US and usually play late in the evening here, it's not unusual for me to have less than 5 opponents on line. The only way I get to play for more than 20 or 30 minutes is to have lots of games going. I would hate to be excluded from certain games because of the bad rep of some other players.
*for example right now it is 10 pm PDT and I have 3 opponents online, none of which are moving against me.*

grenv: I like the idea of a speed rating instead.