For a fanny pack, if you're really concerned, I'd suggest something like a Coke or Pepsi logo. It will look like one of those freebies you get at charity events and doesn't scream "look what expensive stuff I've got!"
Personally, on those occasions when a pack is necessary, I use a
Hawke Micro-Gun Pack. It hides a full size gun (1911, G17, etc.) in a bag that looks barely big enough for a j-frame.
As for vests, there's really little you can do. In cooler weather, fleece vests are popular enough that you can wear one without drawing attention. But in warmer weather, you'll always ping some people's radar if you are wearing an extra layer while everyone else is tearing down to their shirtsleeves.