Location, location, location.
Aspen, CO - price per sq ft = $1,118 (and rising)
Tampa, FL - price per sq ft = $87 (and falling)
Las Vegas, NV - price per sq ft = $106 (slow rise recent months)
Detroit, MI - price per sq ft = $77 (rising/hit bottom?)
Fairfax, VA - price per sq ft = $237 (falling)
Seattle, WA - price per sq ft = $370 (currently falling but up for this year overall)
Houston, TX - price per sq ft = $54 (rising)
Are those new homes only? Vegas and Detroit rising would be good signs of a bottom, and would demonstrate that simply looking at median price of new homes is not a good indicator.