I'm pretty sure I've seen "Pixie Crunch" somewhere before, and the place
I think I might have seen it was at the BYFG grafting meeting last year
or the year before. I just checked BYFG's "Woodbank" and it is listed
there - you might want to check the list and get in touch with whoever
is growing it.
Let me know if you won't make the grafting meeting - I'd be happy to
keep an eye out for a scion for you.