[kibwen]

Most malls I've seen are one-story (rarely two), and given the natural cost-minimizing nature of their construction I doubt that you could just build more stories atop the existing structure (but I'd like for an engineer to chime in).

[smileysteve]

It's more likely you could turn the empty big box store (sears, circuit city) into a complex within itself. You need windows added, but generally speaking 3 outside walls for people to look out

[abfan1127]

I doubt they could do additions. They'd have to demo.