If this is important and you can't seem to track this guy down using any other means (it's true that there is no directory for cell phones), then you have few options.
1.) Find his service provider and see if there is anyway that you can obtain his mobile number by providing his name, address, etc. By law, they cannot legally give that info out, but you never know. I don't suggest you try to break the law, but asking can't hurt. They'll likely say that they can't help you, but you may ask if they could leave a message from you on his account. If you beg and have a really friendly rep, they may help. Explain that it's urgent. You can *guess* his service provider by where he is from. It's hit or miss. If he's from Winnipeg, his mobile provider is *likely* MTS or possibly a nationwide carrier like Rogers. You may have to call around.
2.) Post a classified add in local newspapers in his area (I.e. Winnipeg Free Press) with your name and number telling him to call you. He may just see it. Any old pervert now has your number, but less people will call long distance as a prank than you think. Hey, if you need to reach him, you have to do whatever it takes, right?
3.) Try searching for him on sites like LinkedIn, Facebook, MySpace, Classmates, Hotmail, etc. You may be able to get ahold of him and/or his contact info from there.
Good luck!