Definitely in need of a slim-fitting trench. Raglan sleeves, shoulder straps, gun flap, etc. - basically the works. (I think the raglan sleeves on the TOJ1 are amazing) Strong, dense, black calf leather collar backing - shape to your liking/styling, and it'll stay that way. Horn buttons. Cotton satin fabric.
You've already expressed a desire to create a lab coat for spring. Black satin sounds nice for this.
I wasn't on the wagon with people who wanted an M65 in the past, because I wasn't sure if a good looking M65 could be made. Nineohtoo's recent fit with the undercover m65 is pretty awesome. I think that you could make a better M65 in black satin fabric, heavy duty zips, etc.
Black&Navy Tapered Trousers&Chinos, Black Overdye Denim