here's a speaker that fits what you're trying to do; high end mids with phase plugs and a scanspeak 9500 tweeter, very high end aluminum drivers. The mids and woofers on that are proprietary though made by status acoustics.
http://www.rbhsound.com/product_detail.php?id=8300-SE/R
I'd contact them and ask them how what the impedance for the drivers / wiring they used to get it to work out.