@chris71 I don't usually get the opportunity to comment on Speakers as I have not heard many of the models that usually show up.
I do know Models from Companies referred to by yourself and can be sure there are quite different End Sounds being produced between the Models.
Altec Lansing - Klipschorn - B&W 801/802 D3 or D4
I am also quite familiar with work undertaken by Joseph Crowe and have communicated with him in the past.
The Links below will put you in front of a Type of Speaker Design you have expressed an interest in, as well as numerous others.
Note: That Drivers and Xovers selected by both Crowe and Graveson in the case of certain models are to be found in Commercial - Branded Models costing easily near £100K. Using these designs as a DIY route to produce a Speaker will reduce an outlay to almost parts costs only.
Think Board Material and Cutting at £1K maximum depending on Board Materia.
Think a Cabinet Maker assembling at £500 + £300 for adding a Veneer selection if if this is wanted on the Cabinet.
Drivers + Xovers are between £1500 - £5K depending on the Speaker Design and quality of Xover parts selected.
My own experience of this for a design selected is a total outlay of approx' 50% of the maximum total shown above.
http://www.troelsgravesen.dk/Illuminator-4.htm
http://www.troelsgravesen.dk/Illuminator-5.htm
The B&W D4 when I experienced a demo left me stating it is a Speaker that is a very close mimic to a ESL Speaker when being driven by a SS Amplification. I was really hoping it could have also been heard on another occasion with a Valve Power Amp' but the Speakers are not logistic friendly to be moved to alternate listening spaces.
I have also recently heard the Klipsch Jubilee and was enthralled by the overall experience, but they are the antithesis of the ESL Speaker types I have lived with for such a long time.
I will state, from after COVID and return to normality, my most recent experiences of visitations and being introduced to alternate speaker designs has led me to have a complete rethink about ESL Speakers and I am enjoying Cabinet designs with a new gusto.
Currently I have superseded older owned Cabinet designs and replaced their regular usage with new types of a design for a Cabinet Speaker, it looks like this is to be taken further and another Cabinet design will supersede the owned ESL design.