17 is still pretty scarce!
In a message dated 6/9/2015 11:57:04 A.M. US Mountain Standard Time,
lbickley at
bickleywest.com writes:
I know of 17 PDP-8/S systems, including four at the
RICM.
The RICM has an OMD8S data-break and memory expansion chassis for an
8/S.