As long as you converted the 4k to 1080 proRes with the same file name you can relink to the r3d files in Color or Da Vinci Resolve from the XML or EDL. Color works best with the EDL as you get to change the sequence settings on import to the right pixel aspect.
Fairly sure with da Vinci 10beta you can alter the sequence settings later from an XML import to relink to the 4k r3d files
I can indeed change the resolution to 4k in Davinci 10 beta, the problem is in Smoke the xml is 1920. Just want to make sure the XML is not altering the resolution in Redcine X, as I'm using it for the clips that I need full 4096 on, my problem with Davinci is it only allows 3840.