The original Wolverine and Battlemaster spring to mind. (Though I'm not exactly sure what you're talking about since its been over half a decade since I did any mech designing.) I didn't like all the resculpts of the original mechs and all the changes it caused to their design history (the Locust lost it chin turret, the Rifleman lost it radar wing, the Wolverine and Battlemaster lost their "pistols", etc.).