Here are two vst plugins that emulate a crossfeed circuit.
This one is adjustable:
http://www.ohl.to/about-audio/audio-softwares/crossfeed-and-eq/
This one isn't adjustable:
http://refinedaudiometrics.com/products-hdphx.shtml
This one is adjustable:
http://www.ohl.to/about-audio/audio-softwares/crossfeed-and-eq/
This one isn't adjustable:
http://refinedaudiometrics.com/products-hdphx.shtml