Honestly, I am hesitant to recommend this to you. As a mead maker more then a beer maker, mint has always seemed to muddle the mix for me in the most negative way imaginable.
We used peppermint in a batch of mead, and we were delighted by the aesthetics. After a year of monitoring and aging though, we were flabbergasted when we found out that it was undrinkable. It tasted like intense Listerene and was very bitter.
I do not know how this translates to the beer world, but that is my two cents.