GearDown&Locked,
It is a nice idea in theory, but gear weight is something the designers have been working to get down for many years. Something like that would undoubtably add much more weight and then you have to justify carrying it around to the been counters. The Japanese actually tried to get Boeing to build them a fixed gear 747 version so the weight would go way down and those half hour flights with 550 people on board would be more profitable.
