You might consider single full range drivers. They don't do ear bleed SPLs, and they give up some on both the highest and lowest frqs. Because they don't have XOs, they have a coherence that is missing from all but the very best of multi-way speakers. Good SFRDs have excellent downward dynamic range, so they can sound very good at low volume.
Depending on your room and preferences, you might consider:
--BIB; Bigger is Better back loaded horn which uses corner/ceiling as extension of the horn. easy build.
--Metronome; MLTL floor standing design with high WAF
--small horn like the Frugal Horn Mk3
more info at:
http://www.planet10-hifi.com/and
www.diyaudio.comCheers, Jim