While I built and own a set of Linkwitz Orions and am rebuilding nicer cabinets in the Orion-4 style with solid lumber curly maple baffles, Gabon ebony trim, and zebra wood sides (they will be _much_ prettier than any of the following designs) I'd also recommend looking at
- The NaO Note. The polar radiation is more uniform than Orion (which has broadening dispersion crossing from the midrange drivers to tweeters that is compensated for in Orion 3.1+ with the shelving low pass filter), it should sound even more natural, and it costs less. I have not heard them and hope some one brings a pair to Burning Amp 2012.
- The Gedlee speakers. While flat packs and not the same degree of DIY they're the only speakers more than a couple Orion owners have preferred. I haven't heard them specifically, although I have heard other wave guides paired to large mid-woofers with matching directivity at the cross-over point which produces exceptionally natural sounding results with silly headroom without the cost of the driver displacement which goes with dipole mid-bass. Earl's competence should produce very similar (but perhaps better) results.
For lower output levels than I prefer for acoustic music Pluto works great and makes more sense (sounds more natural) than any box speaker with the same driver sizes, although the small mid-bass limits its headroom (Pluto 2 does 6dB better which may be enough for you). Pluto+ addresses that and provides last octave extension, but by that time your parts cost is getting closer to the other speakers (my Pluto+ build probably ran 75% of what I spent on the Orions; although that was before the dollar got weak and Scandinavian drivers got so expensive). I built/own Pluto+ too.
I'd avoid nearly all conventional box designs since the directivity mismatch between the mid-range and dome tweeter puts a 2-4KHz peak in the first reflections' spectra which sounds unnatural and makes them more sensitive to placement than better behaved speakers like the above.
