I think you can get them everywhere. Thomann has them, but they don't ship to canada, try warmoth.com or something.
Example: http://www.thomann.de/de/goeldo_push...ti_500kohm.htm
look for 500kOhm I think those are the most "sensitive" ones, because EMG uses 500kOhm pots. Hope that helps a little.
Guitars: Ibanez RGT42DX loaded with Dimarzio Air Norton (neck) and Dimarzio x2n (bridge)
MIM strat /w maple neck. new pickups soon
Amps: ENGL Screamer 50 1x12 Combo
Effects: All I use now is a dunlop wah and a big muff.