I'm not an Elite myself, but one of the guys whose travel arrangements I handle will re-qualify for Platinum this coming Sunday as well...SFO-IAH. So this must be a pretty popular week. And his only additional scheduled CO travel this year is IAH-ORD (one-way, because the return is in 1/1/00).
As to the availability to upgrade on the flight from Europe, are you sure the seats are gone or have there not been any allocated? A couple months ago, I called to hold 1st class reward travel to Europe for next June for the person I mentioned above. The trip was being scheduled in conjunction with a Meditteranean cruise, so he wasn't very flexible with his travel dates. I kept being told that on each date I chose, all the 1st class reward seats were gone. I have a little too much experience in dealing with these things to believe that to be true since I was calling 9 months in advance, so then the actual traveler called back. Speaking to a different agent, he was told that 1st class reward travel was blocked for European travel on weekends in May and June. In fact, I specifically asked the first agent if the seats had already been taken or if they just haven't been made available. She said they had been taken!! Pretty inexcusable, IMO, that she didn't know that when this *was* the International reward desk.
So my point in posting this is you may be faced with a similar situation. While you were told the upgradeable seats are already gone, they may in fact be blocked at this time, waiting to see if they can be sold instead.