The SynClavier is still around. My friend has one and recently had it upgraded with the latest possible options. It's still a mythical object, still does some things other machines don't. I think it's the only one in the Netherlands.
Personally, without wanting to desecrate something as holy as the SynClavier, when speaking of comparable possibilities I'd have to go for the Korg Oasys or Kronos. While a Neko or Meko seem obvious choices too, they never offered the complete package and total integrated system that a SynClavier (or Oasys or Kronos) did, instead relying on a lot of third party content. The Korg offerings have a bunch of synth engines, sampling and hard disk recording all packaged into one integrated system. I'm not giving it the same status as the SynClavier because that was incredibly far ahead of its time, and the Oasys/Kronos aren't really. Nor are they as prohibitively expensive. But in some ways, they are a modern an affordable version of one.