Actually, there are 3rd-party mail apps for iPhone, e.g. AltaMail, which I use. There are probably others too, though I have no idea whether any of them support S/MIME.

Your basic point stands, of course - I just wanted to point out that whatever official reasons it gives for App-Store rejections, Apple only "plays rough" with apps submissions when it feels like they challenge its core business, not merely because they duplicate Apple-provided functionality.

Or pants, apparently.. um, which profession did you say you were in, again? :)

Dude, it's your perfect world.. why not just go for the gusto and wish for the actual Natalie Portman?

:-)