Waterloo Wellington Flight Centre is top 5 biggest flight schools in the country. There is lots of flying here (general public, college program students/integrated, air cadets, sight seeing) I know of about 5-6 instructors that have left due to movement in the industry and they will definetly be looking for instructors. The owner of WWFC is also the owner of National Flyers Academy. So if you train with them, you're most likely gonna get offered a job. The probability is alot higher than other flight schools in that area.
Good Luck!