Theoretically—and that is what you're asking—this bill allows any other province that signs an agreement similar to the one in Ontario and British Columbia to join the system and become one of the provinces participating in the regime created by this bill. However, in order for that to happen, there must be an agreement pursuant to subsection 8.3(1) of the Federal-Provincial Fiscal Arrangements Act. If an agreement is reached with any province, under this subsection, a province may join and become a participant. Because of the flexibility built into this bill, the name of a province could be added, as well as a tax rate.
On December 8th, 2009. See this statement in context.