[Steven-n-Donna]

You can get absolute zero mantanence cost by modifying the settings.txt. These setting alow you to adjust the amount in which racial points cost. Example: anything over a 100% of say Defensive only costs 1 racial point each. You can also change it so you can have higher amounts of racial advantages. Like a 200% Attack rating.
Personally, I don't use these, since it makes the game seriously easy unless you go through and modify every other AI and human players' sources.
It takes a bit in the text file to realize what your modifying, just look at the strings, and they are pretty self explainitory.
Steve