I cannot think of any useful digital logic design that is "clock-less" (suspend/resume is in-fact a type of "clock")
It's technically doable - it's called asyncronous logic, there are even a number of CPUs based around it including the GA144 that ElectricMucus has, it's just not commercially viable because it's so hard to design and debug. So in a way I'm actually kind of surprised BFL aren't using it 