Sometimes you find just what you wanted just a little bit late. This happened with the most recent issue of Arospace Projects Review; it had a big article on the Project Pluto nuclear ramjet cruise missile, with some discussion of early designs including a few lines on a reported North American study from 1947 describing nuclear rockets and ramjets. When the article was published, the North American study was unavailable, and was thought to be likely to be a vague mathematical treatise. However, not long after publishing I came across and photocopied/scanned a copy of that very report. Far from being vague, it was fairly massive and contains detaield engineering schematics of a Mach 3 nuclear ramjet cruise missile, its liquid rocket booster, and what is essentially an enlarged V-2 witha nuclear rocket, capable not only of serving as an ICBM, but also capable of sending a payload onto an interplanetary trajectory.
The next issue of APR will have an update article describing these.