I am looking for a replacement to Microsoft's USB Device Simulation Framework (DSF) which is deprecated on the Windows 7 WDK, especially for one supporting USB 3.0
Maybe an alternative would be to plug in a number of physical USB audio devices and then programmatically "unplug" and "replug" them: Simulate USB unplug/replug
Another alternative might be to have a number of bluetooth audio devices within range and programmatically connect/disconnect them: Programmatically connect/disconnect bluetooth headset
As far as I can tell (now that the WDK is officially released), DSF is still available as part of the Windows 7 WDK (on this page below the Win8 WDK downloads) - it's just been removed from the Windows 8 WDK. No idea why, because as far as I can tell, the driver model is the same, and DSF devices created in the Win7 WDK should work in Win8.