$200-300 stems?! Nice alloy stems equal to the craziest weight weenie stuff on the market are like $60. Can't imagine how you can spend $200 except on something claiming to be carbon; stems are a rather poor application for carbon, they're almost never actually carbon, and not lighter anyway. My generic Taiwan 100mm stem ($30) is 107g and plenty stiff for my 46cm bars and 200+lb self. S-Works (alloy) is 110g. I don't see anything more than $150 at JensonUSA today. Anyway -
I have the Salsa Carbon Cowbells, and I think they might fit the bill. Though if I was shopping for a new carbon bar today, I'd have a look at the ergo FSA K-Wing AGX. Looks like it would improve wrist angle on the tops (my wrists are a little sensitive from various injuries)