Price break on luxury condos in striking glass tower in Center City. Best offers over $250,000 considered.  That's the strategy for moving 40 of the 178 units still unsold at the Murano at 21st and Market Streets, to be sold at auction for sums 50 percent below their original list price.  Take the 1,405-square-foot, 23d-floor unit originally listed at $995,000. It could go for $485,000, less than what it would cost to build today...more