The drivers have gone up in price because of the cost of neodymium magnets (vast majority from china). They are what makes these little planar magnetics so efficient. To make a real line source with the Neo Tens, crossed at the 160 Hz he mentions, the speakers will need to be at least 8 feet tall. The tweeter section can be shorter but you would need enough of them to match output and impedance. I can imagine these being a great speaker. As compared to my favorite ESLs the only downside I can think of is having to use a crossover in the midrange. From what I have seen so far dispersion characteristics may not be as controlled as a Sound Lab style ESL. They would be a much easier load than ESLs and way more efficient. Doing them in kit form would be an easy build but you are looking at around $3000 in drivers alone and you have not gotten into the bass yet. 160 Hz is a bit high for a subwoofer crossover and these subwoofers need to be line source to match the rest of the loudspeaker. So, you would need to either build two floor to ceiling enclosures with four drivers in each or do what I do which is to arrange the subs along the base of the front wall making a horizontal line source.
I would think a practiced DIYer could do the whole affair for $8000 which is not bad considering what you get. I would tri amp the whole affair and use digital crossovers. But, will they image? The big downside would be resale value. If you wind up not liking them you are going to lose a lot of money. I have no doubt that they can be made to sound excellent and probably made to image well but there is no way to know that for sure.
