When I was riding a V-Twin, I got a Sabregear thigh pack. It's like a drop leg holster set-up with Velcro and zipped compartments. I got it because I don't like riding with a backpack. It also converts to a sling bag (bandolier style) if you want to use it like a backpack. It worked well for me, but you can't carry a massive amount of stuff.
Unfortunately, it appears Sabregear went out of business during the recession. However, you might look into sling bags or a thigh pack for carrying some essentials.