One thing I'm interested in is in Jitsu. I've tried to find more, but there is hardly anything out there. Can it do/is it easy to plugin something for load-balancing? With a 100ms boot, you could easily scale by starting VMs on the fly.
Regarding the scaling, it's definitely something we're keen to do. For example, we should be able to create hyper-elastic clouds by rapidly spinning up and culling unikernel VMs in response to demand. e.g a simple scenario might be me serving my personal blog from a cubieboard but if a post ends up on HN, then my infrastructure should automatically scale with the demand -- complete with load balancers etc and elsewhere on a public cloud provider. As demand falls, my footprint shrinks back into just the one VM on the cubieboard.
I'm sure these ideas aren't new but unikernels should make them easier to realise.