I agree with you and would like to add (to the author of Hippy): Why not contribute to HHVM (or fork it and improve it)? If you made a few tactical improvements to HHVM that sped it up a bit, and kept a few good ideas in your back pocket, I'm sure the whomever is PMing the project at Facebook would love to talk to you.
Don't want to work at Facebook? I understand that, but before you say no, infrastructure teams at large companies tend to have a lot of freedom and lack of politicos sniffing about. It might actually be quite a bit of fun on the HHVM team.
Don't want to work at Facebook? I understand that, but before you say no, infrastructure teams at large companies tend to have a lot of freedom and lack of politicos sniffing about. It might actually be quite a bit of fun on the HHVM team.