Also out of curiosity, why would you need a cross over for the Magnepan? Isn't it just a single panel?
The crossover was probably for the subs. A lot of people don't like subs with Maggies because they feel that the sub is sluggish compared to the mylar panel.
There are many different models of maggies, though. The 3.6R, for instance, has three drivers per speaker and an external crossover that separates the lows, which go to the bass panels, from everything else. There is also an internal crossover for the midrange panel and ribbon tweeter.