Google Images can't seem to find any but I'm looking for a pix of a bike that has a front mounted rack that mounts on the cantilever. I've seen tons of pix of the rack, but not in action.
I'm thinking of getting a Wald 139 to attach to it. It'll be a much cheaper solution than getting a real porteur rack.

The Salsa Casseroll comes stock with a front rack that attaches on the front canti breaks.

Here's some pics: https://salsacycles.com/bikes/casseroll/

Do a Google search for Nitto M12 bike rack.

Ohh, perfect guys! Wow, the M12 is out of my budget. I was thinking more of like the 12 dollar kinds on ebay that kinda look like the M12. And a 14 dollar Wald 139.
I ride bikes, I'm cheap. I don't wanna pay for gas

I had a Wald 137, a little smaller than the 139, mounted on a Nashbar front rack that mounts on the brake posts as you describe. Nashbar item #NA-FRR. No pics, sorry, but the combo worked really well. Easy to load, easy to keep an eye on, easy on the budget. I was cruising along one evening on a bumpy path and my fork collapsed, and I briefly rode on that basket and my lunch box. The fork died, but the rack and basket were just fine. A good combo.

Disposable! That's exactly the setup I'm gonna do! But I figure I'll get the ebay rack that looks like it. When I order from Nashbar, I tend to get too much stuff!!! I had the 137 on my daughter's cruiser and I decided I want a bigger one.
How did you attach it?? Zips? I want to stay away from zip ties this year. It starting to get a little ghetto

Sorry man, zippy ties alll the way. I guess you could go high class and try hose clamps.