These were end of sales in 2013 and end of support in 2016. So you can't get them from Cisco any more.
I doubt you will find them unless somebody is cleaning out a decomissioned data center or such. You might call one of the reps at curvature.com (formerly Network Hardware Resale). I've had some success with them in the past getting an obsolete piece of gear I needed for a legacy data center that had one fail and needed the same type (layer 8 issue :) ).
