Originally posted by Archimedes the Dog I like the canvas and leather shoulder bag style and I want it to have as much room as my current bag, which holds a camera and three lenses pretty well, as well as accessories like an incident light meter.
My favourite messenger bag (what you call shoulder bag) is the Peak Design Messenger:
Peak Design Everyday Messenger Review - Introduction | PentaxForums.com Reviews
Close second, exactly the look you are wishing for I think, is the Think Tank Signature 13:
Think Tank Signature 13 Review - Introduction | PentaxForums.com Reviews
That bag lacks the Peak Design dividers which I prefer, and the external anchor point for a Capture Clip (which I use a lot). Internal organization was still excellent, and... well, read the review, it's easier than repeating it here.
Another which fits your wishes, is inexpensive, extremely reliable and comes in many sizes is the Think Tank Retrospective:
Think Tank Retrospective 30 V2 Review - Review Announcements | PentaxForums.com
Any of these three are covered for life. The retrospective also comes in black, and the Peak Design comes in lighter gray, black, and used to come in brown (not sure it's still available, except maybe on the Peak Design eBay store).
The ONA bags look very elegant, but I'm not convinced internal organization is in any way better (I have not tested them).
Other brands like Sirui and Manfrotto also have vintage-looking messenger bags, but I have no experience with them.
I hope I helped, let me know if you have more questions.