Hi, all. This post is not spam. I'm just a long-time lurker.
I became obsessed with the Z-600 for a time before the fever subsided. It has been discontinued, but still available from certain retailers in Canada. If you simply must have it you can probably find a way to ship from Cosmo Music.
It's nearest cousin, the Z-555 ( not the same, I know) is also on the outs, but there are still a few available at Amazon for about half the original cost of the -600. Let us know how it turns out!
I really like this desk too. It looks like everyone is out of it. The nearest replacement, the Z250, does not have the rack spaces. The next closest thing (which probably caused it to be discontinued since it was several hundred dollars less and very similar) is the Studio Trends 46" Studio Desk STLD46, available from GC/MF. But is is only 46" wide vs Z/600 which was 77" wide for better stereo separation. Omnirax Presto is ok but seems to bulky. It seems as the years go on there are fewer options.