Richard take a look at this site: http://www.soundsonline.com/sophtml/details.phtml?sku=EW-164G

If you preload the instruments you are going to use for your live performances then there is no lag time switching from one instrument to another. You would just be changing from one midi channel to another. This is how I use instruments such as these within kontakt as my lead or melody instruments. I use Bandstand or LiveSynth Pro for my auto accompaniment with very good results.