All of the manufactures I looked at had a cold weather kit available. Admittedly, the Generac kit was not very impressive as it consisted of a battery heating pad (good) and a heater wrap for the oil filter (not so good)! But, all it would probably take is a light bulb near the crank case to keep the oil warm. My generator also has a cold start monitor that under a certain outside temperature, there is a delay until the generator picks up load to allow the engine to build some heat and get oil circulating.
At -30F and colder for extended periods of time the so called "cold weather kits" are a total joke. You would need a super insulated enclosure for a light bulb or pad heater to make much difference. Not saying it couldn't be done but at what expense? Guess I will have to stick with my little Honda that is kept warm in the garage 24/7.