Regarding drilling...I too considered it "last resort" until I actually did it. It turns out that the designated keys are of standard dimensions and construction, and CAN be had off the inter web for reasonable price. Or, if such a man exists who considers himself unashamed in his pursuits of metal removal from a substrate, Machinery's Handbook contains the taper and dimensions...
Building the drill-jig was simple, and employing said jig was also simple. I just happened to have a drill of sufficient length to finish the task. I'd assume that the Amazon gods would shine favorably upon anyone seeking such endeavors....
A simple electric hand drill was employed for twisting power. A reasonable estimate of intended depth was utilized, in attempts to NOT drill through the back-angle cut into the shaft keyway. I was easily able to prevent such dastardly results.
Yes, the drilling took some time. In total, an afternoon from noon till ~ 4pm was burned (including the making of the drill-jig).
BUT...now having done it, and in possession of said jig, if I were to encounter another stuck key....I'd snicker after a few good whacks with a drillers hammer and some wedges, walking from said Listeroid, muttering something to the effect of, "....you have no idea what kind of violence I'm about to visit upon your insistent soulless life."
And...should a brother find himself entirely destitute, in need of moral and physical support, I'll allow the borrowing of said jig. But....I'm not so keen on same, for the drill bit.