Yet another infrequent update. During the last several months I got the remaining parts I needed to run eight Pis in a cluster. The only thing I was missing was a case. Today I re-purposed a cigar box and stuffed everything into it. I still need to do some cable-minding which may result in some soldering to made everything look nice. One last thing I need to do is to configure just one of the Pis to be an Ethernet-to-WiFi router for the other seven.