Diners Club has a program whereby I can book an airline ticket and pay for it normally, and just use the points to pay for the travel -- this is not the same thing as moving the points to the airline program and navigating that airline's frequent-flyer program, so it's not subject to blackouts or availability. The points I have are worth about $825 worth of airline ticket. My plan -- assuming United Airlines can accommodate me -- continues to be to buy coach tickets and upgrade them to business class using the >120,000 United miles I have. Then I'll cash the Diners Club points to pay part of the coach fare. I can't buy the cheapest fare (around $1100) because they have to be at least "class M/H" to qualify for mileage upgrades, so I'm looking at around $1600 per ticket. (That's just an estimate on account of not being able to price the flight yet -- I tried one month earlier and got those prices.)
Except that I just had a thought looking ahead to 2010. The Diners Club points might turn out to be more valuable if I were to transfer them to my Alaska Airlines account, where I would then have enough for a couple of free business class tickets on QANTAS. But then of course there's the problem of availability, and for that matter, will QANTAS still be partnered with Alaska Airlines in October 2009, which would be when I would need to book the ticket to have any chance of having an opening.