In my experience (which is limited to the world of Alembic-land), it is not really possible to hear the fingerboard one of our fretted basses. When you play, you are touching the string to the fret, and the fingerboard's job is to give the fret a place to live. There isn't any wood that surpasses Ebony's density, ease of care, durability, and downright good looks.
On an Alembic, the choice of Maple for a fingerboard would be purely aesthetic. This may not apply to other basses, but you'll need to rely on your own experience for them, I simply don't have any.
I know that you'd have to convince my mom that you know what you're getting into if it's a Maple fingerboard you must have on your Alembic, and do be prepared for us to try and persuade you on the path to Ebony, it is something we're sort of stubborn about.