Personally, I'd go with an MMG/subwoofer combo. Whatever the cost to the "purist" audiophile approach may be, the extended, smooth bass of the subs and the placement flexibility of the smaller Maggies is likely -IMHO- to more than justify it.
The trick, of course, is getting proper integration. I use the Velodyne SMS-1 Digital Room Correction unit (DRC to the subs, only!) for precise control of level matching and all other crossover variables. It's a PITA to set up, but works like a charm. I also use an NHT x-2 active x-over, ahead of the SMS in order to keep the Velo unit out of the main signal path. More complex than most audiophiles prefer, but very, very effective.
Good luck.
Marty