columns / roof

[oar]

Hi all,

I have to span a square of about 50 by 50 feet with a roof. The roof should have a cupola in the middle.

I am wondering if I can simplify construction of the roof and reduce cost by putting up four columns arranged in a much smaller square in the middle of the larger square. These columns would form the base of the cupola and allow me to eliminate large and complex trusses by having rafters running from the exterior wall to the columns and tying into the columns directly.

If I do this can I achieve significant cost reduction in the construction of the roof.
I do believe that a column supported roof would be significantly sturdier.

What do you think?