If all you want is height, go for a split level approach. Use the 'constrainfloorelevation false' cheat to allow this plan to work.
Here is a diagram of what I am recommending:
FFFFFFFFFFFF
FFFFFFFFFFFF
FFFFFFFFFFFF
FFFFFFFFFFFF
SSSS UUUU
SSSS UUUU
SSSS UUUU
SSSS UUUU
FFFFFFFFFFFF
FFFFFFFFFFFF
FFFFFFFFFFFF
FFFFFFFFFFFF
F = Floor
S = Stairs on the same 'floor'
U = Stairs to the next 'floor'
Each letter being a tile, of course, 12 x 12 building in that layout
For the 4 tile rows on the top side, you are raising them a full floor higher than they should be through whichever method you can make work for you properly, thus also allowing a staircase from them to sit an even 4 tiles down to the original height. When its done, the building should look something like this:
Normal This Method
4444444444444
3333
3333
444444444444 2222
333333333333 2222
222222222222 1111
111111111111 1111
GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
G being the ground, and the numbers being what floor above the ground the tile is actually from.
This design by itself precludes rooms due to space constraints, but the design can be enlarged or otherwise modified to achieve usable spaces on each 'floor'.