Dunno who's the cheapest, but here's a short list for availability:
- Cycle Solutions (Parliament/Carleton and Kingston/Main)
- Sweet Pete's (Bloor/Dovercourt-ish)
- Cycle Motive (Queen/Bathurst)
- Urbane (Queen/John)

As for those cranks, one of the major Canadian suppliers carries them. Any shop that deals with Norco Sales can check stock availability and order them in for you.