I would NOT buy from Vesey's. I wouldn't trust their stock to be free from viruses or even correct.
But there are many good Hosta nurseries which ship.
The ones I've used, in Ontario, are:
Goldenbrook -
http://www.goldenbrookhostas.c...
Shades of Green -
http://www.shadesofgreenhostas...
Hosta Choice -
http://www.hostachoicegardens....
Gardens Plus in Peterborough -
http://www.gardensplus.ca/ I've stopped by, but it appears that they do mail order.
These are three in the Ottawa area and I'm not sure how much mail order they do, but you could ask. All are wonderful hosta sources.
Rideau Woodland Ramble -
http://www.rideauwoodlandrambl...
Whitehouse Perennials -
http://www.whitehouseperennial...
Budd Gardens -
http://www.buddgardens.com/ (I know Don Budd and while he doesn't make a big issue about mail order, I know he does some).
In the Maritimes, Fundy Beauties/Hosta Geek -
http://hostageek.ca/