So Spencer, what can we expect from you in the future? Is your greatest skyscraper yet to come?! I think you should definately knock out the current top 10 tallest before you decide to call it quits!
I've always wondered how you would make the Petronas Towers and the World Financial Center!
Would you make the WFC in a pre-9/11 state so you could connect your WTC to it kinda like your Rockefeller Center buildings? That would be REALLY cool! Plus the bridge behind WTC 6 would have something to connect to! Lol!
And the Petronas Towers could be easy to model using 1x1 round and square plates. Sort of like Brickshelf user
Torgugick's design (I think you had a table next to him at Brickworld 2009). Although his seems like it may be a bit too small for your scale and you always do original designs anyways. So you would probably find a differrent way to replicate the buildings.
Just some ideas to think about....