For anyone who's interested, Noisebug is presently selling the Korg ARP 2600M for $1,600, which is $400 less than the normal price. The reason given is that they're not selling. So, I'd expect the instrument to have a short run.
I've been considering the 2600M, but the more I study it, the more I appreciate the Odyssey as a more matured and better developed synthesizer, especially regarding modulation. With the 2600M, you often have to use the semi-modular patching aspect to make use of even basic functions. Whereas the Odyssey doesn't take the same amount of labor to arrive at a fine and musically useful patch. Even though its panel has a quirky layout, it's still accessible for making quick and substantial changes in a patch.
The 2600M, though, is still a very tempting synthesizer for its overall sound and sophistication. Considering prices these days (and putting Behringer aside), $1,600 is almost a reasonable amount. But it really needs the original keyboard to reach its potential.