A Canadian Answers...
Wow...Sounds like I have to clear my schedule for next Fall!!
Either spot is a great place to visit. November is tricky, though because both Banff and Vancouver/Whistler will be prone to wet mawsy weather that time of year. Being the "shoulder" season, as one of you put it, will reduce hotel costs a bit, that is certain. I can do a bit of research for the organizers and 'suss that out for it, if desired. (PM me.) Vancouver/Whistler will be a going concern as preparations for Vancouver2010 Olympics picks up; I don't know what will be happening in that regard, though. Both locations are easily accessed by international air travel and both provinces are big players in the Rotor industry.
Helijet International ([URL=http://www.helijet.com]) runs a S76 Commuter service in Southern BC; perhaps they are a potential corporate sponsor. Alpine Helicopters may be able to provide the same in Alberta. Calgary is the home to most of the Canadian Oil Companies, so there may be a tie in there as well.
2005 is the Centennial for Alberta becoming a Province; I don't know if there are any activities for the Centennial planned that late in the year, though.
On a good day, both locations are spectacular; and if the Fall wx has been brutal, there is always the possibility of some early season skiing...
Banff is probably the cheaper of the two choices; although I don't know what kind of conference facilities they offer.
Post your questions, I will answer as best I can.
Cheers