Hmm, when I was in a few weeks ago SA said that they see a lot of Herbags in lighter colors (I was lusting after RA, haha, she was smartly talking me down) come in for color transfer. Not sure if that means they do/don't do spa, but would assume that they could at least take a look. I've also read that you can clean the canvas on your own, but gently with baby shampoo (somewhere way earlier on this thread).
Not sure about the straps - but I do know that the knobs on the end screw off so I would assume that they could take apart the leather parts of the bag to replace?