I went through this process late last year. You should be very aware that the great majority of travel agents (in Canada as well as the US) have very little experience with RTW tickets.
I woundp getting my tickets through AmEx travel in Toronto, using the agent Ray Surette (tel 416-967-3411). Overall, I was only barely satisfied: calls were often not returned within a reasonable time, and I generally knew more about the OneWorld rules and process than did Ray. However, he did ultimately get the ticklet written, and he is an extremely personable fellow.
I had much more confidence in an agent named Sophie at the AmEx agency in Montreal (514-282-0445). I had called Sophie when it appeared that Ray would be unable to get the job done, and Sophie seemed to know her RTW stuff inside and out. At the last minute, though, Ray came through with the ticket.
If I were getting another RTW ex-Canada, I'd probably call Sophie first, with Ray as a second choice. For any agent, I would first have a chat and figure out if the agent understands the basics of RTW ticketing.
(Edited to correct no more than 30 typos.)
[This message has been edited by wideman (edited 05-17-2001).]