There was one made by Klotzli, for Spyderco, that had carbon fiber scales. Of course there is the Al handled, Almite coated version available now too. The carbon fiber one was/is very nice but more than many people (the average ELU) want to pay. I don't remember a stainless handled version.
Well, that comparison could go a lot of ways. I'll just give you my personal taste. I think Carbon Fiber is very nice looking, and very strong. For me it is a little slippery the way it is used on most knives. G-10 looks good if you're into the black tactical thing (though it comes in colors) but gives a surer grip. It is also very strong. I have heard stories about carbon fiber chipping when people have dropped their knives. I can't say I've heard that about G-10. To sum up, both are very strong and light. One is pretty, though a little less practical for heavy use IMHO. The other is more practical but not as pleasing to the eye. Hope that helps.