I found an old ammo bag at a military surplus shop. It looks like a small courier bag made out of heavy canvas, with a fold-over flap, and dividers inside. It is the perfect size for the Hasselblad (or Rolleicord), an extra lens, a light meter, and a bag of film. It was $4. Also, it doesn't scream 'camera bag' when people look at it, which I like.
On the other hand, it might scream 'man purse'...
I know of someone who carries that bag but he carries a toy camera with a ring flash.