I had a similar problem, needing a tall squarish building to go around a 7" sq. boxed post in the center of my 'city peninsula'. At York, April 2012, the late (and sorely missed!) Bill Parisi attending the OGR booth showed my wife and I how we could take their new Midtown Hotel (appropriately named, I must say!) and a Bill's Place (also aptly named!!) and cut/combine them into a 6-story hotel that has at least 7" of clearance inside.
It's done! It's great! I need to add a picture to this response....which I'll try to do today. My only regret?...I had hoped to share this success with Bill at the October York. His passing was a real downer for me...as I'm sure for hundreds of others. On the other hand, my wife and I feel blessed to have been given this very special meeting/project with Bill in solving this problem...and getting our 'city' back on track, so to speak.
As Rich Melvin suggested, there probably is a way to use Ameritowne products, as did I. But, it sounds like 'the other' Rich, Korber, has a nice plan on the way for you.
Come to think of it, you are truly blessed...with all sorts of 'Riches' at your disposal!!
Good Luck!
Merry Christmas!
KD