Ash normally says something's discontinued when they don't carry it (this seems to be "Standard Operating Procedure" for them--back when I worked at Ensoniq, they said this about some of the Ensoniq products that were very current at the time.) Also, while doing a search for something else on Soundscape's website, I stumbled on a "3rd party developer" document for Mixtreme, dated 8/8/01--the product appears to be far from going away! (DSP Media can now use them in their workstations, for example.)
I'll divulge new information as I'm able--there's a lot of stuff going on behind the scenes!
Oh, and I have Mixtreme in stock--call me!