Dunlavy ?????

I've owned the III's and I still am using the IVa's. I agree with Rja that the IVa is a big improvement over the IV's with the use of premium drivers which tightened up the bass. These speakers are big, so you need to have the right room, but I have yet to find a competitor at the price point.

One thing not mentioned is your room size. You'll need a good sized room for the larger models, and expect to have to sit about 10 feet away from them for the drivers to integrate at their best. If you don't really need bass below 40 Hz, the SC IIIs might be a good choice, they can work very well in medium-sized rooms. Since they are sealed-box designs they have less room placement problems than a lot of other speakers.

Having owned Duntech Princesses for a long time, I have to agree that the Dunlavy-designed speakers are exceptional--they may not have been the absolutely most transparent speakers, but they did everything at least very well, and they especially got the midrange right. My feeling has been that the Duntechs sounded a little better with solid state amplification, but the Dunlavys really sang with tubes. My opinion, though--YMMV.

One thing to keep in mind of course is that Dunlavy is no longer in business (John having unfortunately passed away), and Duntech is in Australia with a limited distribution network (they were good at getting me matching replacement drivers for my Princesses when I needed them years ago, not sure how they are now).

If you want a moderate size speaker, get the Dunlavy Aletha or Dunlavy Athena speakers. There the same speakers.
They had that cool hexagon cabinet.
They used a 10 inch Vifa woofer, which is facing downwards.
Then a MTM design using two 6 1/2 Vifa midbase drivers and the Vifa tweeter. The drivers you can get easily on Madisound if you need a replacement driver
The speakers have a really nice soundstage and the bass is very tight.
You'll see the speakers come up on Audiogon every once in awhile.
Here's someone that owns the Dunlavy Aletha speakers at a Music studio.
You can talk to him about the speakers.http://imperialmastering.com/the-studio

Another advantage to the Alethas/Athenas, as I recall, was that they could be used in a smaller room than the IVs and larger models, but would give more bass than the SC IIIs.

The final iteration of the Aletha/Athena was the SC-III.A, which I own. The cabinet is a conventional rectangular shape but it's the same drivers in the same configuration.