A quick search on Autotrader.com showed several.
All of the Avalanches that showed up in the search for the term Z-71 were first generation (2002-2006) trucks and none were second gen trucks.
However, when searching for second gen (2007-2013) 4x4 trucks, there were several hits for that term.
It looks like there were no second gen 4x4 trucks listed as Z-71, but rather they were listed by LS, LT and LTZ models.
Now to be clear all first gen Z-71 trucks were 4WD, but not all first gen 4WD were Z-71.
And not all second gen 4WD trucks were Z-71 and there were even a select few second gen Z-71 trucks that were 2WD.
Now, how the Z-71 was distributed across the LS, LT and LTZ models is another question.
I am assuming you are wanting a second gen 4WD Z-71 truck.
If that is true, perhaps a search for simply a 2007-2013 4WD Avalanche might produce a number of trucks that you can dive deeper into to find one that is a Z-71.
Good luck with your search.