"Build up lots of cash. Then buy up the McMansions at the foreclosure sales. :-)"
If I understand correctly the problem with McMansions is that of zoning laws that basically require them? 2 1/2 acre lots that are only allowed one single-family dwelling? It always had me scratching my head. I really can't think of many people who want to bother with so much lawn. Take a drive through such areas and for the most part all you see is souless cut grass. On endless front yards big enough for Uncle Mikey's Neverland Ranch or John Travolta's airplane collection. This, I gather is a consequence of "Smart Growth" or "Keep out, thy unwashed villeins!" policies?