I've been carrying the MobileEdge Scanfast Laptop backpack for a couple of years now. It fits under the seat just fine and would hold all of that stuff without a problem. I absolutely love the 'Checkpoint Friendly' aspect - you don't have to take the laptop out at the X-Ray belt. Have gotten numerous compliments from TSA personnel.
http://www.amazon.com/Mobile-Edge-ME.../dp/B001EHO842