I have a hard time finding refills for my stainless sharpie marker locally. So much so I had to order my last refill off eBay.
I figured out the other day in a pinch you can pull the felt tube and tip out of a regular sharpie and put them into a wore out stainless sharpie refill. The felt in the regular sharpie is shorter than that in the refill so I just made a spacer out the old dry felt to make up the difference.
It just occurred to me that you could make a stainless sharpie in colors other than black using this method too.