Thanks to everyone who replied! I know you guys think your suggestions are funny, but I'm actually writing them down - every joke has a bit of truth in it 
So far:
- Petawawa (someone else suggested it to me)
- Ormocto
- Trenton
- Borden
- and perhaps somehow getting in touch with youth workers at RMC? It's a long shot, but hey, I want the show to have the best possible couples (hopefully military couples)
Any other suggestions?
I already tried: youth centers; kijiji, craigslist; social media sites (25 to be exact)
You know Ormocto is in New Brunswick, right? As opposed to the "Ontario only" requirement you put up?
Negotiating to get a tasteful poster up at the mess halls in Petawawa, Kingston, Trenton, and Borden might be your best bet. Folks see it as they're waiting to get something to eat, as opposed to some random post on a website.