UD carbon fiber is the answer to making a handle bar as capable as the Black Ace.
I've never dealt with carbon bars. Do they work with the ally stems?
Go for it! Don't get paralyzed by thinking it has to be perfect. Compared to making metal frames, there is very little technique or practice required for composites. They are very forgiving of mistakes: you can always sand it off and do it over!
Carbon handlebar on alloy stem?
You can use an aluminum stem with carbon bars, and vice versa if you so chose.
You do need to have the right diameter stem and bar combination though.