Any special issues with putting a wider internal gear hub in a narrower alu frame? Can I safely put my 130mm internal geared hub in a 126mm spaced aluminum frame by forcing it?  What are the consequences?  How would the IGH be "damaged" by this?

My IGH hub has a wheel laced and ready to use, but I would like to use this older, lugged aluminum frame I picked up cheap.

I have heard that steel frames can be "cold set" (i.e. bent), but that aluminum frames cannot.  However, I do find that there is some leeway in stretching the aluminum rear stays, so I think I could force the new IGH hub into the (horizontal) dropouts.  However, Sheldon Brown says that IGH hubs might damaged when you put them on a spacing with the wrong size.  

I'm not sure if I would be effectively throwing away my IGH if I put it on this frame.  Has anyone done such a thing?  Does it affect the IGH?
Do not use a mis-matched internal geared hub for your frame.

You risk damage to your gear hub, your frame, or both. Aluminum frames are much stiffer than steel frames, which is good for good for riding, but it is also prone to cracking due to this stiffness (when compared to steel's malleability). Even if you do fit the part, it will be a weak point in the frame.