Not wacko, just not safe nor will it work for a few reasons. I don't think there's enough space between the holes of the two different patterns to fit nuts and weld them. IF there is enough space, that much welding would not only weaken the hub, but keeping it from warping would be difficult. And last but not least, Subie wheels are hub centric and most 5x100 are lug centric. Since you have to machine the centering ridge off the hub, Subie wheels wouldn't center correctly anymore.

Ahh, good points. I don't mind having ideas that don't work when there's a good reason, and those are good reasons it would be bad.

 

So would subaru 5x100 rims work? Because the pugs have to be lug centric, the nubs on the hub don't line up with anything inside the wheel.