Steelharp, try Cylinder & Slide, Colt referred me to them when I was looking for a series 70 Gold Cup slide. They had a new one and it was reasonable.(pretty hard to find item). I don't have their address handy but do a web search and it'll show up.
Steelharp, thanks for the thanks. gunpartscorp.com has Combat Elite slides for $210.55, item #400610, they also have the Enhanced Combat Elite slide. Just left their site $108 poorer than I was 10 minutes ago.