I suspect that the only things that will really fit...and look right...will be MB supplied...and will cost more than any reasonable switch ought to cost.
That being said, could you do something with one of the blanks? Maybe drill a hole in it and mount a panel-mount toggle switch? The MB blanks seem to go for a couple of bucks, and a panel-mount toggle would be similar - you could even get an illuminated switch!
2015 Solera 24R
2014 Mercedes Chassis