I have a couple of Bags-Connection tank bags that use the SW Motech gas cap mounting system. They clip on and off real easily, especially my small one. The small one ("Daypack") doesn't even touch the tank. Extremely convenient for running around town or day trips. I can even fit an extra face shield in the small one without sacrificing any capacity. The larger one ("Engage Sport") uses a strap in front. Still real easy to deal with. I glued some felt on the bottom of it to protect the tank, but normally only the straps touch the tank.
I got them from my Triumph dealer, but
Twisted Throttle carries them. I ordered a camera mount from them that is part of the same system.
As for tail packs, I still use a backpack, which I have modified to fit real well. The bad part of a tail pack is you look a little dorky getting on and off, and you shift the center of gravity up and to the rear. However, if you like leaning on the tank, a tankbag gets in the way.
