Psst. I'll give you one of my patents, gratis.
It's a carbon fiber structural paint.
By the time those buildings wear out the internal steel, you'll be able to just paint it on and forms a hard candy shell!
(Cut me on 10% of the savings, willya?)
Sorry dude, the company I work for already makes a carbon fiber epoxy shell for just that purpose.
BTW, it makes great gift wrap for that secial gift that takes a couple months to open.
(My little brother and I have been giving each the same fruitcake with riginal wrapping for about 20 years.)