I'm a big fan of scale rockets. I built my Estes Saturn 1B over the winter, also built an Estes V-2 immediately after. The real V-2 had so much nice surface detail, including the fin fairings, that a 3D printed one would be nice. The Estes Maxi V-2 has nice detail, but tough to find.
I'll echo the comments prelviously from Oberon, about a Pershing. I've got resin parts for a 4" model but they weigh a ton.
Finally, not scale, but I just finished a Mars Lander. Those upper paper shrouds were a pain. I'd love to see the body as a 3D part, or parts, to go with conventionally built legs.