I'll be watching this one, too! Regardless of how it turns out, at least working on it will be a pleasure (nothing like the smell of cherry wood when you're working on it!).
I bet the yew sapwood will work just fine as a backing. As for other woods, I know there's an older post on PA about a gent who made a maple backed cherry ELB for his wife (it even looked like a very, very clean piece of yew). Maple would be a good backing that wouldn't overpower the cherry, either. As soon as I find a local source of quarter or rift sawn maple, I hope to experiment with that combination.
Good luck with the experiment!