Alt Bike Culture - OCC schwinn stingray modding

I've purchase a frame of a 3 speed model of the OCC Schwiin Stingray and am looking to build it up into something fun to ride. I'm thinking about using a Sturmey Archer internally geared hub. My biggest question is can I extend the lenghth of the axle to make sure it fits into the amazingly wide rear forks. I have a stock wider bottom bracket that will made the chainline work but I think regular hub axles are too narrow to work. I was thinking about getting a nipple and short pice of axle welded on to the end of the hub Does anyone have any thoughts on this plan or better suggestions?

Are you planning on lacing the hub to the original wheel? If so won't the hub be narrower than the wheel? I don't know if that matters but it will be odd. I was thinking that maybe some kind of rig that would suspend the axle in the dropouts would work. Like the way that a bike is attached to a trainer. That method holds the bike on the trainer securely so it may work in this application. Welding to the hollow axle is probably tricky. If that thing inside can't slide correctly the whole thing will be useless. The Nexus hubs are available from Shimano in different sizes but I still don't know if they would be available that wide, those dropouts on that little bike are really wide.