I recently tried MELT Sandwich Co. for lunch through a catering order. I had the peanut butter and jam with bacon and cheese sandwich (they gave me vegan cheese by request) and it was really tasty. I did not ask which gluten free bread they used.
I was told most of their sandwiches can be made gluten free. Everyone else really enjoyed their sandwiches so I imagine the other sandwiches are good as well!
Melt Sandwich is located on the second floor of the Bell Tower near the pedway to Edmonton Tower.