Every time I see an FPGA article, I feel a little sad that Tabula[1] didn't make it -- 1.6Ghz clock and reprogrammable on the fly. RIP.
There are a lot of open FPGA efforts around. I hope someone else gives the idea another shot.
While we are on exotic approaches, Achronix' first generation was using an asynchronous (1 GHz) fabric. I regret I didn't get a chance to play with that before the pivoted to a conventional fabric.
Space-Time ran hot, but I don’t see why they would be using more flip-flops than with a conventional FPGA. Also my sources were pretty clear on the cause of their failure.