do you mean like a wire grill on your kitchen oven or a grill like a griddle pan with the lines in?
theres no way you should eat anything cooked directly over a naked petrol flame, even if you could stand the taste, but you could use a cast iron griddle pan on any stove i think.
i make toast and garlic bread by toasting it in a completely dry frying pan, but thats using bought bread not baking from scratch obviously.
i can reccomend the coleman sportster 533 and its smaller brother, they can be a lot more robust than lighter mountaineering stoves, and do actually run well on unleaded. some manufacturers claim their stoves do but need cleaning out all the time.
and you carry a fuel supply for it on the bike all the time, but these days i prefer the cleanliness of a isopropane canister for short trips