Well, I too love my little 400. After purchasing I went out and
bought a few different cases to see which I liked the best. The one
I use the most is this expensive ($50) Tumi cell phone case. It's
really great for my use. Great construction, metal belt clip,
magnetic snap.
That looks like stiff material (nylon?). If there's any movement of
the camera, I'd be concerned that, over time, the edge of the flap
would rub against the camera case and remove the finish (despite it
being "Cerabrite").
I'm already having problems with the belt loop on my Canon-brand
case wearing through, due to rubbing against my stiff leather belt.
It's not quite the same thing but whenever there's a chance of
movement, you'll also get friction, and ultimately abrasion.
Tony