According to wikipedia (
https://en.wikipedia.org/wiki/Mercedes-Benz_Sprinter), Mercedes has offered a 1.8 liter inline 4 gas engine to markets outside North America since 2014. The engine produces 154 hp and 177 lb-ft of torque. The current 3 liter v6 diesel produces 187 hp and 325 lb-ft of torque.
The website mbvans.com (
https://www.mbvans.com/en/gas-engine) describes a 2 liter turbo-charged gas engine which delivers 188 hp and 258 lb-ft of torque. Looking around the mbvans website, it appears that the v6 diesel is about $6300 more than the gas engine. The gas engine is limited to the 1500 and 2500 models while the diesel is available on the 2500, 3500, 3500xd, and 4500 models. The 3500 has slightly more payload capacity than the 2500 (with either engine) while the 3500xd adds about 1,000 pounds and the 4500 adds another 1,000 lbs.
The mbvans website also has a section on cab-chassis models (
https://www.mbvans.com/en/sprinter/cab-chassis) which indicates that cab chassis models are only available with the 3500xd and 4500 chassis.
All of which leads me to conclude that there may be cheaper gas-powered class-B's coming, but that the class-C market will continue to be diesel only.
Dave