If it don't exist, then nobody's gonna find it, next best thing would be to send the CD with it on to some friendly musicians and see if they'll learn it for the event.(Seems odd suggesting live music is the "next best thing" to karaoke) alternitively you could persuade your D.I.L. to perform it acapella.
I found a karaoke site with a track with the same title by Deanna Carter here but I don't think it's what you want.
good luck bugsy, hope you find it.