For new, the Soma Double Cross comes to mind - nice frame (Tange Prestige) for a reasonable sum. Velo Orange sells some decent frames that are aimed at the transportation/commuting/brevet/randonneur crowd, with a retro flair.
If you have the cash, Rivendell would do the trick.

For retro, Guerciotti used to make some really nice cx frames in the 80's/90's if memory serves. Otherwise old Trek or Miyata touring bikes would be nice options.