I'm a product manager for two of the largest consumer electronics product lines in the country at the 2nd largest distributor in the country. While some of the ideas above are excellent, I'll point out why it's just not possible in the current canadian landscape.
At the moment, every canadian supplier is basically a small business. While this offers a lot of variety for suppliers, it also has the secondary effect of none of these suppliers having enough liquid assets to be able to support having everything in stock all the time when you want to order.
Although it would be extremely handy if there were some sort of distribution network, or someone with enough liquid assets to support a large scale operation, the relatively small size of the industry compared to say consumer electronics means there isn't enough overall revenue to support this level of inventory/service.
Holding inventory costs money. It's basically the same cost as borrowing money which is in the range of 0.02% per day. This assumes your supplier has an excellent credit rating, otherwise the cost is MUCH higher. The longer the inventory sits on the shelves the more money/profit is lost. This means most of these smaller vendors will tend to keep only their top skus in stock at all times (depending on their overall size). As most of these vendors are using 3rd party web-based software to manage their inventory, overall inventory management is poor. Until vendors start using back-end software to support a more advanced supply chain (which takes either programming and supply chain knowledge, or large out-of-pocket expense) they cannot realistically manage a high volume of individual parts with any efficiency. Few vendors even take backorders for this very reason, they simply list the product as "out of stock" with the option to notify the buyer when it's back in stock.
To my knowledge there is no "centralized" canadian distributor for e-cig supplies thanks to our lovely Health Canada and their fear mongering. If the product was relatively accepted by the government I would be shocked if large scale consumer electronic distributors didn't want to pick up a product line with such a high Y/Y growth. This means every vendor is buying direct from a number of different manufacturers. They are either paying for ALL of this product up front, or are able to get some sort of credit terms with these manufacturers. If they are buying on terms with all of their suppliers they either need an extremely good credit rating, or need to keep inventory as low as possible while keeping their inventory turns high to avoid damaging their credit rating.
Now, couple all of the above with potential shipping delays from China, and product seizures from our customs dept, and it's basically impossible to have that "god" vendor that sells every model of every device with everything in stock all the time. Hardware, you're looking at potentially 500-1000SKUs by the time you include all accessories/options, and that's just looking at the big manufacturers. Add in the Mod makers and the sky's the limit. E-liquid gets even worse when you have at least 20 different canadian "manufacturers", and probably close to 200 in the US, each with a variety ranging from 20-100 different flavours / strengths / mix ratio, AND this product has a shelf life.
Now with all of that said, we have some truly excellent vendors in Canada considering the daunting task of managing a technology that is literally changing by the day. I feel for all of you and the financial risks you need to take to keep your customers happy. Sadly until this product gets some positive recognition by our own government, I don't see this changing any time soon.
edit add Temco to list for my wire
