It sucks because it would mean that all housing codes and all standards would have to be rewritten.
On a personal note not a bit of it other than meters, centimeters, or millimeters makes a damn bit of sense to me.
They're already doing metric construction in government contracts. Check out the
NIBS "Construction Metrication" newsletter and some of their other publications. And besides, a half inch pipe isn't a half inch, and a 2x4 isn't 2"x4" anwyay.
One of their past issues had a story about the tricks they had to use to redo the Pentagon on a metric grid. Also, a lot of the high-end shingles these days are a meter long, instead of three feet.