While I can't comment on if anyone has ever gotten one to work with a modern PC,
I can comment on the SDL port not accepting merely any SDL cord you stick in it.
I've seen more than a few posts of someone buying a Model M, and then decided to buy a much older Black plastic SDL cord from an older M to "improve" the look, and then finding out that they don't work.
I wish I had access to a resource that would neatly explain which keyboards accepted which SDL's, but more than likely, the only SDL's that will probably work on it will be cords from that era (Span of 2-4 years), and that is still a pretty big shot to take.
I'll hang around though to see if anyone has any ideas, This would be possibly the coolest macro keyboard I've ever seen by far.