Kinda depends more on the teams you face than the position of the build. If you play against a LOT of QB running teams, I'd build monster CB's (heavy with a LOT of strength and tackling skill). If you face a lot of heavy passing teams, I agree with the Beaver. (always wanted to say that.)

If you face a lot of Power Back running teams, then DT's or LB's are the ticket.
Overall, if I really wanted a lot of tackle attempts (then, of course, build a dot that can tackle well enough), I'd go with MLB. It would need a damn good build but should be able to cover the field well enough to be in on most tackle attempts (so speed and agility to get to the ball carrier would be primary skills).