Soleri, an architect, thought about this a lot over the last 40 years or so.
Building materials are not scalable the way you imply.
The materials in the bottom would not be strong enough to support the stuff above.
The plumbing and HVAC problem would be much more massive than you can account for with the "feasible" toss off.
That said, check out this website:
http://www.arcosanti.org/
I think you will be pleased.
Ed
