Just got a mail that the Buttkicker Gamer 2 are in stock again. Grab one fast.
This was the unit I wanted to buy when I was looking for one. Ended up putting it together from different parts instead but this is the easiest way, as far as I know.
http://shakercentre.co.uk/aspbite/products/products.asp?intProductsID=3
Personally, I use the windows "Stereo Mix" device to double the audio so its always in my headphones (And buttkicker) and the rift at the same time.
Set Playback device to your audio out (Realtek High Defenition Audio?).
Go to Recording tab. Right click the background and select "Show disabled devices".
Right click "Stereo Mix" and uncheck "Disabled".
Click "Set default" on Stereo Mix.
Click Properties on Stereo Mix. In the Listen tab, click "Listen to this device" and select "Headphones (Rift Audio)".
In the Oculus Home desktop app, go to settings, Devices and click the Rift headset. Select Audio Output in VR: Windows default.
Tada. Of course, this messes up programs that uses the default recording device as a microphone. In these programs (Teamspeak etc), you now have to select the microphone device to listen to instead of "windows default".
Now you can just take off your rift and put on the headphones for youtube etc without having to change default output device.