Not yet but I plan to install some Firepro S9150s I found on Ebay for that sweet double precision. The server can fit 3 but the electricity would be astronomical and my PSUs would no longer be redundant.
It isnt a fulltime Boinc/Gridcoin rig as it is running my Firewall, NAS and a few other services in VMs but I have 1 x5650 Boincing, keeping my apartment warm fulltime.
I'm not sure that makes sense, my 2 X5650 retailed at 999USD each, knowing the local market here, they wouldve cost more than retail at release. If people want to know current value then maybe a snapshot, like price as of 1st of Jan 2018. Something along those lines in my mind makes a tad more sense.
It may also be interesting to plot the prices of the hardware by month, to see what the historical return was. An interesting thought but a ton of work that only few may find interesting haha.
Keep up the great content, absolutely love reading your analysis'