So! I am starting my plan of creating a useful, engaged, hub of Montreal crafters. Here is my non-exhaustive and (hopefully) ever-expanding list of Montreal craft retailers
Ariadne's Knits (http://www.ariadneknits.com/) - knitting, crochet [Sud-Ouest]
Bonnidee (www.bonnidee.com) - scrapbooking [Pointe-Claire]
Brickpoint Needlework (http://www.brickpointneedlework.com/) - needlepoint, knitting [Westmount]
Jeannette's (http://www.jeannettes.com/contact.html) - needlepoint, embroidery [Snowdon]
Boutique Jennimar & Sheila (http://www.jennimar.com/) - needlepoint, emroidery, crochet, knitting [Dorion]
L'Oiseau Bleu (http://www.loiseaubleu.com/iiix/home/) - general craft [Laval, Montreal, St-Hubert]
Mouline Yarns (http://www.moulineyarns.com/) - knitting, crochet [Sud-Ouest]
Omer de Serres (http://www.deserres.ca/) - general craft chain [various locations QC, ON]
Scrapbook Star (www.scrapbookstar.ca) - scrapbooking [NDG]
Sial (http://www.sial-canada.com/en/) - pottery, moulding, ceramics, copper [Laval]
If you know of a craft retailer that I've missed, please email greenstockings[at]gmail[dot]com and let me know!