If you have a sentimental attachment to your bike, seems to me trading is never the option. I think if money's not an issue, it'd be pretty damn cool to have a custom bike that you put together yourself like that.
But if you like the bike but think you could do better with a new 1700 rigged up the way you want, it'd sure save you some time. The 1700 is more powerful, but not so much (I'm going by what I've seen, since an on-paper comparison is all I can offer having owned neither) that you'd miss not having it. But there is some merit to a Nomad or Voyager being ready to go out-of-the-box with no fabbing, painting, or putting together required.
2011 Victory Cross Roads, crimson red
"There is only one God, and His name is Death. And there is only one thing we say to Death: 'not today.'"