I used to work for a high-end dealer who tried lots of amps that didn't work. Finally found that Primare(from Scandinavia) finally was able to open them up. Their stuff is relatively new to the U.S. so may be hard to find, but it's very attractive and built like a brick craphouse. I've since moved and have recently been to another well-resepected high-end store who also coincidentally found Primare to be a particularly good match for B&W. On a relative scale it's also priced attractively. Best of luck.
Tim
Tim