Well, just about any wine yeast you use will take the mead to dry. If you want a sweet mead, maybe using a liquid sweet mead yeast will help, but even that may take you to dry. It SHOULD leave some residual sweetness, though. I think it's called Wyeast Sweet Mead yeast or something like that.
You can always ferment it, then after it's finished, you can stabilize it and sweeten to taste if you're not planning on bottle carbonating it.