Source for classic dome trackpoint caps?

[lparsons]

I'd like to put the original style of trackpoint cap onto my T510 keyboard. I've seen it called "classic dome" or "eraser head" but I can't find a source for it. They seem to have all but vanished, I can't even seem to find them on ebay. I personally like being able to grip the edge of the cap with my finger tip, which doesn't work with the flat top caps (and I never liked the tiny nubs sticking up on them).
Anyone have a reliable source? Searching a little further on google I found a couple companies that I have never heard of before claiming to sell them, though none that list on ebay or amazon.

[theterminator93]

http://www.trackcap.com/

[cadillacmike68]

Are you referring to the ones that feel like they can rip the skin off your fingers?