I'm considering the purchase of a performance cruiser in the 40-42 foot
range: I'm looking at Sea Ray, Cruisers, Formula and Rinker all with
gasoline engines. I realize that gasoline engines can pose more of a fire
hazard than diesel but what I'm curious about is in modern vessels, how
significant is the difference in the danger?

The boat will be used more as a weekend getaway on a medium-sized inland
lake than as a cruiser so I thought gas engines would be more economical in
the mid to short-term. i.e. rather significant lower cost of acquisition.