As reported on various sites, Starwood is running a promo where you save 35% on buying SPG Starpoints when purchasing 5,000 or more, up to 30,000, through December 29. Some talk about if you already purchased the standard 30k max this year, you may still purchase up to 10k with this promo.

FAQ states there's bonus points when paying with SPG Amex... does that include the Canadian ones?

If it does, with no tax, but bills in USD so tack on the 2.5% foreign currency fee, buying the max 30k, I think it works out to ~2.8c/pt CAD. Not bad, not a slam dunk though.