If the MM isn't enough, then Warpig or Ceramic Warpig are pretty much the only other options.
Surprised you feel the need for more bass though, even in my alder strat - a very bright guitar - the MM's output & bass response shakes the floor. How close do you have the pole pieces to the strings?
Perhaps I'm showing my age, but MM is more than enough for this aging metaller (FWIW, the Holy Diver is my fav pickup). I've stayed away from the Warpig so far - you can have too much of a good thing IMO... :)