Many estate coffees are going to be lighter roasted because there are special attributes of the coffees they don't want to mask with dark roasting.
There are some estate coffees darker roasted. But at that point, you're gradually tasting more of the craft of the roaster than the beans.
Look for a high end roaster who has estate coffees rather than start with an estate.
Good luck. Let us know if you find something you really like.
-James