Saga update:

Ended up talking to Special Member Services. Even though I was really Silver, they couldn't get me into F, but they at least bumped me up like 13 rows into some preferred seating, so they tried. I think I spent more time on the phone tonight trying to get into F than I would have spent there, but what else is there to do in a lonely hotel room but talk to the great folks at Delta!

Thanks to everyone on FT for their help on this thread. Delta tells me my status change should indeed show up on Saturday. The supervisor at the reservations line said the newbies didn't know what they were talking about when they said I wasn't eligible until 2008 for Silver status.