Achronix plans to deliver FPGAs that run at gigahertz speeds over a wide range of conditions. They have limited information on their site, but they claim to be using some asynchronous design method, which begs the question: what is being clocked at gigahertz speeds? They got back some silicon prototypes in April and two days later announced a low-power initiative, so I wonder what the power consumption specs of that prototype looked like. They plan on supporting user-programmable speed and power, which has really interesting implications on an operating system.
In terms of economics GOPS/Watt may be a more important metric than GOPS/(Fixed Cost) especially if long device life amortizes fixed costs. GOPS/Watt is most critical in battery powered applications.
Anyway, according to my unified theory of reconfigurable computing, these kinds of devices live and die by software support so we'll just have to wait and see.
--Edit June 10, 2008:
Cornell's Asynchronous FPGA group has Technical papers about the research that lead to Achronix products.