It should be possible to run a relay inside a unikernel. Then you can have multiple relays per box.  

 You can easily do it better with docker, no kernel needed 

 This is more efficient. No syscalls 

 More work.

Docker will let you easily run as many relays as you want on a host  

 Auditing is much easier.  

 Lets see what you can make with it.
I never seen anyonebuse those  

 Nginx runs in it. So a static site at least