Absent a better organizational method, for now I will put sites in alphabetical order and ebay sites in a separate listing at the end.
Linton Outdoors - Outdoor gear
I purchased two Eberlestock packs from here. Very good prices, they have package deals or include a free item with each regular pack purchase. Very good selection and they ship to Canada for a reasonable price. Even with customs fees, much cheaper than any Canadian retailer I could find; the Canucks didn't have the colours I wanted and didn't have much selection.
http://www.lintonoutdoors.com/
On/Scene Tactical - Kydex sheaths
He has a very lengthy list of sheaths available plus does custom work. He made three sheaths for me and all were good. I especially was impressed with that he called his operator's rig - he made a more "standard" kydex sheath and a molle-compatible sheath intended to be semi-permanently mounted on backpack straps or molle straps.
His prices are very good, the service was great (he answered dozens of emails with no sign of impatience), he was a genuinely nice person. The sheaths were made within days and I got them quick.
Note: Canadian Seller
http://onscenetactical.com/
Raven Concealment Systems - kydex holsters and sheaths
I bought a sheath for my Cold Steel SRK knife. Sheath was excellent, very impressed. Took a long time to get (4 1/2 months). Prices are high but so is the quality. Holsters look excellent but I don't own any [yet]. Friendly service, answered my emails promptly.
http://www.ravenconcealmentsystems.com
Safe Zone LLC - Mora Knives, Cold Steel Hawks, paracord bracelets and much more
Highly recommend them for Mora knives, excellent selection and prices, ridiculously cheap shipping to Canada. Best place to get a Mora 511.
http://www.safezonellc.com
Ebay sellers list - I have had good experiences with the following
Merry Outdoors - very good shipping prices to Canada, a decent selection of knives for good prices, several items purchased no problems.
The Sharpest Store On The Web - a very well known and large store, mostly use it for knife sales. Excellent selection. Prices are good but shipping to Canada is expensive, you'll have to contact for a quote, better to get a few items or the shipping may not be worth it.
Wholesale Knives and Swords - located in Canada, a real plus, you can avoid the occasional customs charge. Has a good knife selection and has some of the more unusual weapon items that collectors enjoy. I've made a few purchases, no problems.
Rnkcity Outdoors - larger store, lots of great knives, good shipping, no problems. They also sell Maxpedition items for good shipping+purchase prices. I've bought a lot from this store, no problems.
EzeeDeaL - they do sell knives but I often go there for non-knife items, usually for Maxpedition items. I've bought a lot from this store, no problems.