I think you may be on to something with the Morel driver idea! It seems that the 'issue' most people have (the ones that have it :-) ) with the 2Pi's is the piezo driver. So maybe putting in some form of HE, soft dome, horn loaded driver instead would be an idea... & the cross over doesn't need to get THAT complicated. Btw., I believe Peerless are making such a thingie as well.Have someone tried anything of this sort? Maybe a HF compression horn w. driver?
Just a thought... ;-)