This may not be quite the breakfast type thing you were thinking of, but I just got back from a glacier field trip where we had to be up and working at an ungodly hour, in cold weather and didn't want to stop and eat until well into the day. Re-heated dinner type meals keep me going a lot longer than typical breakfast foods, stuff like pasta with diced chicken and veg in a cheese sauce, wok dishes with beef and veg and sauce and wholegrain rice. More protein and fat than my usual double decker sandwiches of wholegrain bread and cheese.

A bowl of fruit would be a nice addition, to get started.