Windows Audio Capture Driver for use with Windows Media Encoder

I'm looking for an audio capture/pass-through driver to be built for use with Windows Media Encoder. Basically, it needs to capture audio from the sound cards Line-In, and instead of passing it directly through in real-time, we need to be able to delay it by a changable amount of time (ie, delay audio by 500ms, 1000ms, 1500ms, etc) This will need to be able to be captured/usable though Microsoft Windows Media Encoder. It'll be used to simulate the kind of delay you experience watching streaming video over an internet connection.