+1 Maple board.... just a slightly damp cloth every once in a while to clean the gunk off.
I oil my rosewood boards with the purest lemon oil I can find once a year or so. Unless you live in a very, very, very dry climate, that should be plenty. Dunlop and a few other companies make lemon oil that doesn't have a bunch of stuff in it (like some furniture polish) for rosewood and ebony boards.
I believe I saw that Roger now has some fretboard oil on his site, that would be the safe bet, and even though it wouldn't be that cheap, it would last almost a lifetime.
I'm not sure about the Morado boards used on the Metro RV.. they are very hard and shiny and seem to have a finish on... not sure if they ever need oiling. I never owned one, but the ones I played seemed to have a finish on them. Might just be shiny, hard wood though. I assume someone 'in the know' will comment on that.