I dont see how your putting more stress on these parts than when the engine is running at WOT and your hanging the plane on the prop. I've stored my planes nose up hanging from the prop/crank for years with no dammage to the engine, seriously they are not that fragile. All the parts you've listed were designed specificly to "carry loads" way in excess of what you do to them by hanging them from a hook. IMO

That being said I do like LearnedinUK's system, very neet. I guess I have to go to Home Depot today and buy some shelving supplys

Darren