Mr. Fong (man of few words, ref link) saw the persistent PHP bet and pointed out that SysV IPC with an external-to-apache PHP deamon will do the trick.

Unfortunately, I locked myself into finding an apache module that would provide a persistent interp. Dang! I should try thinking outside the proc more… but we had a fun and lively discussion for a few minutes in the office as a result, and that’s worth at least $1!