Hi, Chris. Personally, I would not proceed without having the plan checked by a structural engineer. I'm not sure what the lack of footings will do and I believe that your local climate and soil conditions will be a big part of the answer. The engineer will want to know how far down your walls really go also. And, if he agrees that it can be done, I would ask about having drainage put in since you had the dirt dug up anyhow.
Depending on your lot and area, I would look at a pole barn building. It might be about the same cost and a lot less work for the same square footage.