He's obviously out of some quality stock. Alberta has some very nice Clyde breeders and I'd put out some feelers to them seeing if they can offer some background on him. The foal crops are relatively tiny so it shouldn't be too hard. Even if he was never registed, there should of been a stallion report filed (the year proir to his foaling) and you might be able to narrow things down.
www.clydesusa.com is the US organization. They can direct your Canadian search. He most likely came from a "backyard" (hate that term but not someone who makes a living with breeding and raising Clydes) by the simple observation that he has a full tail. People in the biz are going to dock the tail the day they are born. There is good money in hitch geldings right now and he would of easily ended headed that way if he came from a breeder.