How about these?
http://www.ebay.com/itm/331970300009?ssPageName=STRK:MEWAX:IT
http://www.ebay.com/itm/172349229987?ssPageName=STRK:MEWAX:IT
Looks like that second one works with two magnets. Not sure about that.
I just purchased (stole them really) nos gray Superfeet insoles for my sons junior skates. He really likes them. I don't know anything about Superfeet until following this thread.
Ya, I love doing things like this and I'm very detailed (anal) orientated. But our local shop charges $35 for eight sharpenings and I only have one player in the household.