Has anyone replaced the spike on their axe? I have a Grivel Air Tech Racing that I love, except for the aluminum spike. It looks like I could drill out a rivet, remove and replace the spike, and re-rivet it.

A friend did basically the same thing. 'Cept he removed a traditional steel spike by drilling out the rivet, cut the shaft shorter, and reattached the spike. He's pretty handy, and had access to a sweet machine shop, so it looks pretty pro.
Where would you get a proper spike to replace the angled aluminum one? At least, that's what it sounds like you're doing...

That's what I'm doing. I haven't gotten that far with it yet. Still exploring options.