Why not join the Royal Marines? As a Canadian you're automatically a member of the British Commonwealth, so you can join the British Royal Marines without going for citizenship. Of course that would involve moving to Britain and also the Royal Marines Recruit Training Course is 32 weeks compared to 13 weeks for the USMC so it's a huge commitment, but if you wanna join the Marines without going to all the effort of becoming a US citizen, it's a possibility.
