Mike, I know Schiffer books published a couple of titles on German and Soviet armored trains. But I wouldn't say they had "complete" 3 view drawings. The Russian magazine Modelist Konstructor had great plans but they were in Russian.
I share your pain. There's been very little published with scale illustrations. The whole 1/35 market seems to have done very little as far as artillery. There are no US 3" guns or 90mm AA. No Russian 37mm or 85mm AA. Perhaps with the cheaper 3D prototype machines available now, someone will tackle artillery pieces at a reasonable price.
There's a guy under "davesdrydock" selling nautical themed plans on Ebay, but I managed to get some detailed AA mountings from him. His store is called Plans N Things.
Try Google; I found a book on early QF British arty on mhobbystore dot com that includes scale plans.