I searched everywhere but can't find a single one for sale. I ran across the photos of these online. I forgot they even existed.
Were these any good? Must have been available at a time I wasn't interested. Would be cool to get them to see what they offered.
I have the Korg Opsix which is fun and kind of the same form factor I guess.
I didn't research the other two - but you cannot find the DX10 because it never existed. It was a concept floated by "the people" and not Yamaha.
This article shows all 3 and is more crediting Yamaha for this conceptual design. Any way you cut it - these were never real and floated by some entity to stir up conversation.
Source: https://www.amazona.de/top-news-yamaha-synthesizer-an10-vl10-dx10/
Current Yamaha Synthesizers: Montage Classic 7, Motif XF6, S90XS, MO6, EX5R
Here's another one
https://www.synthtopia.com/content/2014/12/04/should-yamaha-make-these-digital-synth-designs/
That does ring a bell but what a good job faking those photos. I think the reface was Yamaha's belated answer to that conceptual idea.