I made brackets that bolted into the existing rear fender mounts and tank mount on the frame. Doing so gave me the flexibility change things if I ever need or want to and I didn't have to do any welding on the frame.  I changed my tank and rear fender, and moved my battery, but you could keep it as simple as you want.  

If you want to keep the stock fender, you may need to use shorter bolts to free up some threads for the bracket.  Or maybe longer bolts that will protrude all the way through the frame to give you some studs to mount the bracket on.  

There are a lot more pictures in my build thread: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1472222031/0

Other ideas:

Build thread: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1371091600



Build thread: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1480200232/0