Tiger Direct seems to add PST and the new $25 levy after the fact. So, some hidden costs, but shorter delivery time. So, your tigerdirect quote is a bit low. Plus, they accidentally charged someone a $50 brokerage fee, so be careful. And their 12 mo. manufacturer warranty seems to be incorrect (Rio's is 90 days), so if you buy from them, capture that screen in case you have to hold them to it, down the line. Blister pack is just put in a box without packing foam, so it bounces around a bit, too, I've read.
ecost.com and etronics.com ship through the Canada Post service, borderfree.com, which guarantees the full price, up front. I've used them and like it. But, it could take up to 18 days to get in to Canada. I'd choose the faster delivery time and then cross your fingers.
Future Shop is said to be bringing in Karma in late Jan, early Feb for around $550. In Caanda, Future Shop and Best Buy pretend to comepete against each other, but they're actually the same company. So, they often carve up product lines, between the stores.
Nitrus has just appered in Best Buys at $299CDN, as the MSRP is about $429, I believe. To give you an idea, the Chibas are going for $329 at Best Buy, so I think they've made a pricing mistake. If you want a Nitrus, act quickly or pre-order at the price, in case it is a real mistake. It must be a mistake, as it costs about the same to ship a Nitrus up from the U.S. through Borderfee, which is unusual, as electronics are usually jacked up in Canada.
Keating Technologies in Markham is distributing Rio products in Canada. They're located in Markahm and have a website with contact people for the Rio line on their site.
Hope this helps.