Here's a slightly different slant. Last week I tried using my leather fanny-pack to hold my T2i with 2 lenses. It was too darn crowded, but I liked the quick availability and comfort when sitting down.
So I explored a bit & found the Plano Softsider 3380, which is a small fishing-gear bag. Interior dimensions are about 9" x 5" x 5" ... quite big enough to handle my needs. The material is synthetic canvas-weave fabric with a rubberized inner bottom. The top is zippered, but I think I'll be able to just use the velcro closure. It's NOT padded, and I might add some thin padding/divider, there's room... but being tight on my waist, I'm a little less worried about hits.
The as-sold condition is set-up for shoulder or bike carry, and has the waist-strap connections tucked inside the back panel. I got mine in tree-camo from Walmart for $17.96 (listed on the web from $14 to $35); it also comes in blue.
There are a bunch of other models - this was just another quick buy-to-try.