The Western Flyer from Tom Bihn is a small duffel/backpack conversion travel bag designed for quick trips or minimal travelers.
Other Bags to Check Out:
The Viken from YNOT is as simple and sturdy a duffel as a modern urbanite could ask for. And it expands. Just lovely.
The Stor backpack from Trakke is a lovely 30L pack for travel and gear moving.
Expensive, but it's got an amazing warranty. A simple, understated, powerful bag that will gladly see you through anything in life.
The Travel Duffel from Aer is an excellent "trunk style" duffel bag, but with a whole smattering of modern travel tools like laptop storage, water bottle storage, and tech organization.
The ATD1 is an expandable backpack you can use for both travel and daily carry. Looks pretty damn good too. One of the best in this category for sure.