http://en.wikipedia.org/wiki/Gran_Turismo_5
"In an April 2008 interview, game creator Kazunori Yamauchi revealed that 150 people had worked on Gran Turismo 5 for three years"
If release is in March 2010, that's another 2 years. So total dev time is 5 years with 150 people.
150 people x $100.000 = 15 mill per year
5 x 15 = 75 mill







