Arcam AVR-300 receiver that comes with the feature of using the unused 6th and 7th channels (if you're only running a 5 ch. set-up) to bi-amp the L & R fronts. I looked around for any other Rcvr that had this feature but couldn't find one. I emailed B&K to see if this was possible with their 507 but I was emailed back that it is not possible (and not reccomended). I don't think this really addresses your situation but it's such a cool feature I thought I'd share.
Happy Listening!
Happy Listening!