Here is one more for you - I am just finishing my first build and took it for it's maiden voyage tonight.
Mounted on the stock rear rack with some foam padding underneath the tank to stop vibrations and a mounting plate below the rack that I drilled into an approx 3x6" piece of steel plate I picked up at the local hardware store for about $2. The fuel line is 3/16" fuel line I bought at Napa Auto Parts - they sell it by the foot. The setup is very solid.
Not the best pics but I only had my cell phone camera with me tonight.