So Icon has these really nifty peices of gear call icon cloverleafs. they are (in essance) a kneepad you can strap to ANY set of pants you want.
I have been looking to get a set of riding pants (of a full track suit [$1500!]) to get something with knee pads for I can go have a lot more fun with my riding buddies at night. Looks like I found a much cheaper alternetive (these are about $200)