Excellent info here. I decided to give this a go with my HP ML110 G7. Got a HD6450 for £20.
I knew it was not going to be straight forward to set this up, but the installation of the card and configuration all went smoothly and I've now got a VM using the HD6450. However the problem I have is I've been unable to get a keyboard recognised. I've tried about 4 different ones without any joy. The mouse works and shows up as HID-compliant mouse and works but not the keyboard. Anyone have any ideas ? much appreciated.