R3D -> "software-which-cannot-be-named" -> DPX -> Photoshop -> PNG/JPG -> Vegas

a bit slow and clunky, obviously, but it works for short clips...

At the moment, "general distribution" outside of theaters maxes out at 1080p so the Vegas 2k limit is not a factor for me. Maybe someday I'll see something I've done projected at 4k, but I doubt it will be this year or next.