Natural gas heating options for basement
We're excavating and plan to finish the basement of a duplex. Currently, the basement is heated with a few scattered electrical radiators (as is the entire building), but we're considering a central system to heat the basement and first floor, since the basement ceiling is completely open and accessible:
1. Electric air furnace with transits to heat the first floor. Pro: no need to get a gas hookup. Con: should I replace the 100-amp entry with a 200?
2. Natural Gas furnace with first-floor transits.
3. Natural gas boiler with radiant heat for to-be-installed basement floor. Steam radiators for first floor?
Does there exist a combination boiler/furnace that will allow us to gas-heat water for a radiant basement floor and use hot-air transits for the first floor? I'd like to get rid of the numerous first-floor basement heaters without having to replace them with radiators.