Are there any current high end dipole speakers (dynamic)?

The M3si is a very special speaker and your going to have a hard time finding a suitable replacement I'm sorry to say.  I wish I had a suggestion, but I'm on the hunt myself.  Another issue is cost, your going to have to spend some serious money to find something in 2020 that's full range and has the same HUGE soundstage.  Personally, I'd keep them or if your on the East Coast, sell them to me. :)

I was at the XFI Premium show in Veldhoven, Holland end of last month and can recommend Spatial and Pureaudioproject. Lots of good sounding rooms but these two appealed to me most. Open, spacious and natural. The bass does not slam but what it does do is provide great insight into the lower registers.

OB bass is sometimes a little lightweight but never boomy. Also the figure-8 radiation pattern is, in most rooms, an advantage. Without the booming the entire frequency range is clear and informative. I am using home built OB and will not bother with box types.

If more bass is needed then I very strongly recommend OB servo subs and I will be building some to augment my set-up.

douglas_schroeder's wind analogy was just 'shootin' the breeze'  :) What happens behind the speakers matters. Everything matters.

Whilst in the PAP room I chatted to ZEV the designer who is from Israel. A nice gentleman who will supply parts to the DIYer. The pair I listened to used used a Voxativ driver for midrange. There is a model that uses a horn but were not available to audition. Out on demo I think he said. He has a model using 4X15" drivers, 2 up and 2 down D'appolito fashion for those with huge rooms or need more bass.

The Spatials also really great with all the charms of OB

Speakers have many qualities e.g. forward/laid back, how much bass, soundstage, etc, but I"m interested in one very appealing quality related to these designs

Audiokinesis pointed out:
--Both dipoles and bipoles result in higher reverberant-to-direct sound ratio [vs typical direct radiating speakers)].
--"at a good seat in a concert hall, the direct sound is strong and the reverberant sound is strong BUT (and here is what largely differentiates a good seat from a poor one), the early reflections are weak."

mijostyn describes the advantages of dipoles [over bipoles] with respect to reducing early reflection and states

"Getting a bipole to perform like this [reducing early reflections] is difficult, maybe even impossible."

Perhaps the higher reverberant-to-direct sound ratio (over conventional direct radiating speakers) itself provides a large amount of the benefit (of dipoles/bipoles) and the added improvements of reducing early reflections beneficial, but lesser. Dolsey isn’t the only person to tell me that I might have trouble finding suitable replacement for the mirages, and maybe the Mirage folks have gotten other things very right, unrelated to this issue.

@mijostyn " A dipole is special because it radiates in a figure 8 pattern. It radiates very little to the sides. A bipole is omnidirectional radiating in a circular pattern. The dipole limits early reflections in the room."

I have bipole speakers. They are not omnidirectional, but front- and back-firing. There is far less sound to the sides, compared to the front and back. The sound to the sides is ca 8-10 db lower. Early reflections can be further reduced by toe in.

@o_holter 

All basically true, but the bipole still qualifies as an omnidirectional speaker especially in relation to a dipole. You still have to treat your room as if the speaker were omnidirectional. Toeing in just changes the position of the first reflection points. This will change the reflections in the room dramatically. You are left with either your hearing to adjust it or digital room control.