Here's a few more, I didn't check about shipping to Canada though... (I'm a big newb, so there may be many other places to buy).
http://www.reidsupply.com/aDetail.as...On=1004254&ST= http://www.roton.com/acme-lead-nav.aspx?line=Acme http://www1.mscdirect.com/CGI/GSDRVS...IT4NO=48398183
eBay might be good too...
Also you might wanna check out...
http://www.kerkmotion.com/default.asp