I was inspired to that header by the look of this Think Tank sling bag. It is roughly the shape of a small continental loaf. Though it is intended for use with cameras, it would be perfectly suitable for a small continental loafer.
As you can see it will swallow a mirror-less system - that's an Olympus E-Pl5 and three lenses. You might want to change the layout inside to accommodate something larger - those dividers shift with velcro holders.
There is a paper and pens slot on the front, an ipad mini slot in the back, and a weatherproof over-cover in a pouch in the bottom. The strap is curved and comfortable.
For the walker or rider this would seem to be a perfect carrying case. If you're down-sizing and weight-reducing your gear, give it some serious thought.
