I've been looking at the same thing after running across..
http://www.praxissystems.com/
http://www.airkewld.com/pages/welcome.php
http://www.ridetech.com/
It seems that you CAN have a performance oriented air ride suspension setup. I think it warrants more research. Do some reading and you will see that there are quite a few good handling street machines that are running air bag suspensions.