Many thanks for the info pwFoo! I really should go about test this myself asap, but have been busy developing my first PW site
I'm not sure the .htaccess file should be a too big problem. For rilpartner.se, .for example, we are successfully ourselves using nginx, which has its own URL handling, and I could easily add the single rewrite rule needed to get it to work ... and I from what I've hear, hhvm should be able to run with nginx, using fastCGI / fasterCGI.
Will also report if I get the time to test this out more!