Well,NetLimiter is pretty good(and the ONLY one that i've heard of really!)
Too bad it doesnt work with Vista x64.
Might wanna wait for a New version,shoot an email to them asking them for a Vista X64 version.
Not sure if this is exactly what you are wanting, but this tutorial will show you how to change the reservered bandwidth for the QoS traffic handled by the QoS Packet Scheduler.