bipole\dipole surrounds to match b&w

Im running the 600 series 3 across the front and was considering the small 600 series bookshelf for the rears. I was hoping for a bipole or dipole alternative but b&w doesn't seem to carry anything like that cept for there older ds6? which appears to have a paper tweeter with a limited freq range. Any suggestions for a bipole or dipole that might match up well with the b&w's?
I suggest you look at the various dipole and tripole surrounds made by M&K. I think the M&K tonal balance is similar to B&W's, and they should make a good match. (If you look at my system listing, you will note that I am using M&K SS-150 THX tripoles with my Vandersteens.)

The M&K web site contains good information about their various models. Here's the link to the page describing their surround speakers:
Thanks for the suggestion, Those k-4 dipoles look like they are worth checking out.