Thanks for sharing Nick. When I was looking at the minidsp, I was planning on using it for subwoofer filtering/management only. The plan was to use a PLLXO for the high pass as I'm doing today.
Someone here recommended a DBX driverack to sort out a different, complex system. I compared the free software download for both side by side, I noticed something that the minidsp was not advertising. The driverack offered phase rotation as a direct setting. It's possible that I've just not found this setting with the minidsp. It does have a nice selection of filtering for each channel however.
I've theorized the implementation of "all pass" filters accomplishing the same as phase rotation with DSP. I found some discussion in the link below that looks promising, although a bit more complex.
http://www.diyaudio.com/forums/minid...orion-asp.html