First of all, I should preface my remarks by saying that most countries on Earth don't have a state immunity act. To the extent that countries apply customary international law and follow the normative hierarchy of peremptory norms and norms of international law, in theory all countries that don't have a state immunity act can follow what Bill C-483 proposes to do.
As to what courts so far have found states to be non-immune with regard to the crimes that are targeted by this bill, outside the United States, Italy and Greece, none.