Hey Jamesbond007,
We are in India and will probably end up FIREd in Hyderabad, simply because we own a flat there. We have done our own calculations and it really really depends on how much you plan on spending. We currently spend around 15-20K a month excluding rent and live a fairly comfortable life. Your child's education might play a big role and also your healthcare requirements. Both are widely available and decent options in all ranges are also available.
Hyderabad is perhaps one of the best cities to plan retirement in today. Prices are reasonable than Delhi, Mumbai or even Bangalore as long as you know where to look. With a lot of IT and related jobs, OKish expat population it is quite a mixed environment.