Quebec is "done"
Yes, Quebec is awesome, as has been mentioned a few times already in this thread. I grew up riding my bike in Quebec before La Rue Verte was created and finally rode parts of it last year during my X-Canada ride. Definitely the best organized group in Canada with signs on the roads identifying the different Rue Vertes. (As an aside, I have to say that in general, Quebec cyclists really, really disrespect the rules of the road - but that's another thread, eh?).
One could argue that PEI's rail trails - which I didn't like because it took me away from the 'action' - is 'done' also. Nova Scotia seems to have a well developed system of bike trails although not quite as formalized a Quebec's, IMO.
What we really need is a NATIONAL organization in Canada, a la ACA, for touring cyclists who want to ride multiple provinces. I'm not convinced it's economically feasible to start such an organization in Canada, but the ACA certainly has all the resources in place to be able to accomplish this. Granted I haven't read much more about ACA's raison d'etre other than their 'about page' but I don't see anything that holds them to just 'doing' the US (and yes, I know there are small forays into Canada). Anyhow, ACA seems to be very well positioned to augment their US routes with significant Canadian and Mexican ones. Just think of all those Boomers with money burning a hole a their pockets! ;-)