Is there an oversized bearing you could go to that still retains the same internal diameter? Or you could machine a brass insert? I would check the price of a hub(new and possibly used), price of a used wheel and your machining options. I would think a place like mongoose engineering could have some options for you on the machining side of things, unless of course you have a guy?
I would think to properly machine the hub you would need to de-lace the wheel, so that might factor into your options.