I think they're winding it down, but NEC still sells (or until recently sold) a version of their SX line of vector 'supercomputers', the latest iteration of which comes on PCI-e cards. Runs Unix and has things like a CUDA-compatible stack.
The SX arch is a couple of decades old now, and racked up a bunch of notable accomplishments back when a 'supercomputer' meant more than "keep piling commodity chips up until you get the benchmark numbers you want". An elegant weapon for a more civilized time.
NHR@ZIB actually has on of the older models in their NGT pool (the OS info is a bit out of date), https://user.nhr.zib.de/wiki/spaces/PUB/pages/428842/Next-Ge...
If you are interested in this model, and part of a German educational institution, you can get free access to it.
There is at least one semi-regular user but we haven't seen a lot of interest in these types of accelerators. The overall userbase appears to value portability (and the ability to run code locally) to a good degree, which these cards often limit/reduce.