Another project building traditionally application-layer functionality directly on top of a Hypervisor, ClickOS -
Of particular note (transcribed, can't seem to copy out of the PDF?):
"ClickOS images are small (5MB), making it possible to run a large number of them (up to 400 of them in our tests). ClickOS virtual machines can boot an instantiate middlebox processing in under 30 milliseconds, and can saturate a 10Gb/s link for almost all packet sizes while concurrently running as many as 100 ClickOS virtual machines on a single CPU core"