First issue: If the plugins (Most are highly customized) run under forkerserver, will they be expected to run under pre-fork without modification? I'm trying to recall some of the discussions, and I think the issues were with pollserver - something about async code(?).
If I recall our own similar migration correctly, things went off nearly without a hitch from forkserver to prefork. You might want to think about whether your customized stuff makes any assumptions that every new connection gets a new process, e.g. if you have some sort of ugly 'our' stuff that's supposed to be per-transaction; if so, your code is kinda broken anyway :P
IIRC, our hook_pre_connect stuff did assume it was running before the fork, and (IIRC again) on prefork it runs after the fork; at any rate, we moved some things to register() that belonged there in the first place to alleviate the problems we had with hook_pre_connect
-Jared Inbound and outbound email scanned for spam and viruses by the DoubleCheck Email Manager v5: http://www.doublecheckemail.com
