Please fill out your profile. With posts like these (no profile) no one has a clue as to what make or model Jeep you are referring to.
If you happen to have a CJ, YJ, TJ or JK then if I recall correctly there is a company that makes something like you are asking about already. I canít recall who but a Google search should lead you to it.
to the forum.
Been thinking a bit more on this and I think that the product I was referring to is just the rounded part to either side of the cowl and not the section just below the windshield like you want.