Are you familiar with the S&S couplers? Having a frame builder add them and then the repaint job would not be inexpensive.
There was a thread recently on adding them to a Mk II Nomad, that is here:
http://thorncyclesforum.co.uk/index.php?topic=14501.0If you are in USA, when I was considering having couplers added to my titanium bike, Bilenky is where I looked but in the end decided that I only needed one S&S bike and my Nomad Mk II met that criteria.
If you are serious about a Mk III with S&S, you probably will find that 26 inch wheels are the best option for packing it.
My Mk II is the 590M size, it is a tight fit to pack.