I'm generally always a big fan of going to a good quality custom barrel over any factory barrel so my vote would be to go that direction.
As to who's custom barrel to purchase, there are many excellent barrel makers out there and it's almost harder to pick a bad one than it is a good one.
We all have our favorites, mine are Hart and Krieger, I've yet to have either that didn't turn out exceptionally well, but I am sure Brux, Lilja, PacNor, Bartlein, and Benchmark, would suit you well also.
I'm not a real big fan of any barrel much smaller than about a #4 contour so for me personally, that is the smallest I would go and to put it in perspective, a fluted #4 weighs about the same as a Proof carbon fiber wrapped barrel.
Do you have a certain weight class of bullets you plan to shoot, what twist are you thinking about using? I wouldn't use anything slower than a 12 twist.