The term V-berth is something of a mislabel when applied to the C-310. We still call it the v-berth, but it would more accurately be called the forward berth, since it is essentially a walk-around berth. One of the reasons we bought the C-310 is that a couple can lay down with their heads either forward or aft. Reading lights are installed at the forward end of the berth, which work very well for us.
We have always used standard queen sheets and folded the excess material under the mattress, but a custom fitted sheet would sure be nice!