same here, my index.php files are both giving 503's
however my admin.php website is still accessible.
(i custom built all my pages, and this is happening on test and live environments)
EDIT1: The most recent post on http://status.x10hosting.com/ is that an exploit was patched 10 hours ago...
This has also happened to me, I had a wordpress hosted in http://p337.x10host.com and now its completely gone.
all my post data is gone, (the files are obviously re-createable)
Hopefully someone can let us know soon!