I've gotten old City of Brampton lights before (a Powerlite B2255 and a Powerlite R47).
Niall (Gailgrove) had a contact with the companies that serviced the traffic signals in Brampton a few years ago and so he let me have a couple of lights that got recently removed as part of a intersection upgrade and was bound for the scrapper. I'm not sure if he can still get you lights as he has been busy the past year.
The major companies that service lights in the GTA are Enersource, Guild Electric, and Stacey Electric, you can try calling them and see if they have lights they're willing to sell.
If you don't mind driving, check Kijiji for lights, I've seen a R47 on there before. Also try going to Active Surplus in Waterloo, they had a B2255 the last time I was there. While you're in the Waterloo area, check the Restore there if you're interested in vintage lamps and Southworks Antiques if you're interested in old traffic lights.