Not much to show for two months, but I think I have enough done now to move on to digitally designing the rest.
The long "rectangular box" (as I'm calling it) that spans the whole height of the side of the building was rather difficult to incorporate against the continuously curving column and window structures. It was also difficult to keep it slim enough to allow the windows on the sides to stay visible all the way to the top, while keeping it broad enough to cover the unsightly middle gaps of the curving sides near the bottom.
I also had to modify the design of the middle "slice" of the building to allow for the opposite end to be attached in the opposite direction when the time comes.
Since the remaining 20+ floors are consistent rectangles in plan, I can definitely design the remainder digitally. I'm running out of extra parts anyway
Hopefully the next time you see this, it'll be the finished product (not to mention the right colors)!
More pictures on Brickshelf