I've said this before elsewhere, much of the engine and transmission could be placed away from the crankshaft ends. If the clutch and the pull start come off, that takes nearly half the width out. If a KO/China Girl style gear and manual clutch were then adopted, it wouldn't add much back in, and it would remove the need for a separate starter.
The next question is whether or not removing the fan is going to kill the engine. Provided it is driven slowly, I don't think so, but somebody would have to make one like that and report back. Probably, but not guaranteed, from the roadside.