You could do that, sure. That's a great idea, actually. I have designs for speakers just like you've mentioned, some with Eminence 8" and 10" format midwoofers and some with JBL 2012 and 2123 large format mids. Until the early nineties, all π speakers with a woofer larger than 10" were three-way designs. This configuration is really attractive for cornerhorns and there are several participants on this forum that have 'em built that way. Probably my favorite seven π of all time was the 1980's model, having a 2205, 2105's in front and back and a 2405. That was one I owned myself for several years, so maybe that's why it became my favorite. I've considered bringing out an "audiophile series" with this configuration, instead of my earlier plans to provide a TAD-based product offering of the same name. So I'm with you 100% on that one - It's a great design choice and its only drawback is increased parts count and another crossover point.