I really dig this kind of custom something that looks factory https://www.jalopyjournal.com/forum/threads/for-sale-1958-chevy-el-camino-custom.1085395/ and It's for sale here
I built one as a model in my youth, long gone, with the same engine set up with a four speed. Using the supplied front seat and removing the middle section of the roof re-incorporating the stock rear window it looked proportional. Kept the curved down section of the trunk for a tailgate and all of the chrome trim of the Impala model. Wish I kept it or at least took a picture.