I finally upgraded to X1 in June and see from my account that I got Zeta+ 2.1 at the time.  Now I've upgraded to X2 on a new computer and done all the installations, but there is no "Download" link showing for the listed Zeta+ 2.1 (although there is a link to the free "Mutant" patches).

That appears to be the only product on my list that isn't letting me re-download.  Anyone know why?

Click the download link to the X1 production suite. The Z3ta+2 installer in on that page.

z3ta+2 isn't part of x2 or x1 but it was included in the x1 "complete package" . z3ta+ classic is included in x2 - see specs under instruments http://cakewalk.com/Products/SONAR/X2-Producer/Default.aspx.  if you did download the installer at the time, just re-run it.

ah scook! "PRODUCTION SUITE" - that's what it was called.

Yes, there was a promotion called the First Class Upgrade that offered the Production Suite as an upgrade to SONAR 8.5. That is when I bought into X1.

Thanks, guys!