Virtualizing Specific Hardware?

Is there any Virtualization program that can emulate specific hardware? It'd be nice for testing apps on older specs.

This would be very tough. All virtualizers available today only emulate a very small set of standard hardware devices. If your device is USB based, it may work inside a vm. The biggest drawback about vm is the lack of hardware supports.

Well, to be fair, that's also the main benefit of virtualization as well - you can take a virtual machine from (for example) VirtualPC on one PC and move it to another, and the "hardware" in the virtual machine stays the same.