I recall that there's a way to dissolve away the backing, but it's not nearly as easy as lifting the fp100c emulsion. You can do it with fp100c with hot water. I tried that on fp100b and... nada. But some enterprising people have figured out an acid bath or such. I recall the thread was here on apug a few months ago.
One experiment I've been meaning to retry is to enlarge a b&w positive to fp100c, and then lift that. If the enlarger balance is just right, I think you'd get what you want, a kinda-b&w lift. I tried it once but the color was off (the blacks looked a bit purple) and I didn't have time to play with filtering. A projected b&w slide looks b&w but, thanks to the enlarger bulb, it's not. If the light source is exactly the right color temp, I think it should be possible.
Anyway, all things are possible if you put the time and thought into it.... Land himself would be doing precisely these kinds of experiments, just for fun, if he were alive today.