I've been sitting on these photos for quite a while now, as I was hoping someone would also send me a picture of the burger itself. Sadly that hasn't happened yet.
The cart has just reopened for the season, so I figure now is as good a time as any to finally post these pics.
Looks like a cool place. The signature burger is a beef patty topped with havarti cheese, grilled green peppers and "19A sauce". Sounds like a winner. I hope to give it a try sometime this summer.
ps. Thanks to Jaimie and Colin for the photos.