I haven't heard of any others, and your comment said 'supercomputers'.
Not to mention that the NSCA was just throwing spaghetti at the wall to see if it would prove useful when it came to the PS2,[0] and their setup never worked reliably.[1] The PS3 had several supercomputers made independently.[1][2][3]
and the fears that Saddam Hussein was going to buy a bunch of PS2s because the cpu was SO POWERFUL they would be used for missile guidance systems or something
They're not, because they don't lock down the hardware to only Steam.
If they subsidized the cost, people could just buy them as general purpose computers and not buy steam games on them.
Valve would only be in a position to subsidize the hardware if they locked the hardware down to just the Steam store.