Hey thunderbrick,
I've got a Behringer analog crossover you are welcome to use. You could have true stereo subs crossed low. Feed your big Maggies full range and bring up the Dahlquist subs around 40 hz. Hell, I'll even UPS/FEDEX it to you so neither of us have to drive. OR, I could bring it down to Rolla if you promise to play some tunes on your system for me.
The Behringer is XLR only, so you'll need to buy some adaptors from Parts Express, but other than that, you're set. Let me know if a
free crossover is a good deal for you.
P.S. I think the Dahlquist idea is KILLER!!!!!