I've often wondered if serial computers could have a useful role again. At very high clock speeds and wide data paths, you hear about trouble controlling signal skews. In contrast, imagine a serial computer clocking data around at 8 GHz vs. an 8-bit computer clocking data at 1 GHz. You have to deal with faster speeds, but no skew, and it seems like a 1-bit ALU might be simpler (and faster) than a 64-bit one.