Every one of those old-school sheetmetal louvers were sort of rounded and MUCH less agreesive then the Shelby ones. Not saying a talented sheetmetal guy could not do it, just saying you'd better be sure of what you are asking for.
On another note, those extractors behind the front tire on the A/C Cobras...are they available without the fender? If so they could be bonded on easily and I think they'd look great in the top of a hood.
Edbert, it all depends on what dies the guy has that are available. Most of the dies are too rounded, I agree, but there are some that aren't. I've even seen a hood done with a set of dies that made the louvers vary in length, plus if they go in like CP suggested, the roundness wouldn't be seen as much.