Some Ontario school boards have pretty good gifted programs. A few are cutting them, that's true. The Toronto District School Board has gifted programs starting in grade 4, and they continue to grade 12. Ottawa/Carleton has excellent gifted programs, although they have waiting lists for some schools. Halton District School Board is going to expand its primary gifted programs this fall.

I would check the websites for any school boards near where you plan to live to find out what gifted programming is available. JavaBean, are you in the Kingston or Niagara area?

Licorice26, I thought that the Vancouver School Board provides gifted programming, although I don't know what grade it starts in.Primary Gifted (grades 1 to 3) is pretty rare in Canada.

Some high schools offer Advanced Placement courses and other schools offer the International Baccalaureate. Again, you need to check the Board websites for what is offered.