I bought my XS in the Spring of '04.  After riding it for the summer, I have fallen in love with it.  I love the XS!  Anyway, I figured it would be a great bike to build a chopper out of.  After doing lots of research on various designs and methods, I decided to make my own.  I bought a stock '79 frame, tripletrees and forks on ebay.  I wanted to save my current frame- eventually I want to have 2 complete bikes- a normal '79XS650 SF, and an XS650 chopper.  So I'm scrounging for all the parts to make a new bike.  I digress...
        I cut everything off behind the rear downtube so I could use the stock motor mounts, then I added and bent tubing to make the frame I wanted.  I used 1" 1020 DOM tube (.120 wall), per the wisdom of far wiser sages of the XS650 group that have tread this land before.  I had a friend of mine order it through his shop (a sheet metal business), and most of the welding, bending, and cutting took place there after hours.
         The manipulation of steel is a fascinating thing to me.  I'm a fairly hand guy with wood and design, but to me it is still amazing that with the right tools steel is simply another "wood" to be cut, drilled, routed (or more accuarately, milled), and sculpted into the shape you desire.  Building the frame has been incredibly rewarding.  As a teacher, at the end of the day I can rarely look at my classroom and say "look what I did today".  Teaching is much more insubstantial than that.  I often envy my friends in the construction trades- at the end of the day they can look back at their day and say "I did that".  In teaching, those moments, while much more significant (in my opinion), are also much  fewer and farther between.  Maybe that's why this has been so great so far.
          Anyhow, here's pictures of the modified frame.  I have the rear wheel mounted on it right now.  I'm deciding how to mount axle adjustment plates yet, and I'll add them soon.

       Next (actually before I started the frame) I bought a tank on ebay from a 2004 Harley Dyna Low Rider.  I got a great deal on it- because it had a big dent on the front LH side, and didn't have the dash with it.  Here are the pictures of it from ebay:
      

       I can bondo, so I went to work on the tank.  For the hole on top, a welded patech sealed it, and bondo filled it and the dents.  This is the current status of the tank, with some bondo and primer.  I need to finish sanding it.  I will wait to do filler primer until I am ready to paint it.  I'm sure it will get a scuff or two before then.