Another large four-engined beast that I would love to build was a high altitude long range recce craft- I think it was called the XR-1 Rainbow, and I think it was built by Fairchild. I believe Anagrand did a resin kit but it was very expensive. Beautiful plane- pencil thin fuselage, very streamlined nose, high aspect ratio wings. I have a book on it but couldn't find it now.
A very nice model. Republic XF-12 Rainbow in 1/72 by Anigrand. I was building the aircraft that mounted the R-4360 engine, but literally ran out of shelf space.
Bill