Didn't do it with Dividend Miles, but this gem of an opportunity came upon myself and many other Starwood flyertalkers in 2001/2002.
At the time, the Starwood --> Qantas ratio was 1:2. That, on top of their 5K bonus for every 20K transfered made it probably the best, cheapest way to get tix on the Concorde, or any BA First class trip between the US and UK (both 125,000 RT).
How? Transferred 100K Starwood points to Qantas which earned 250,000 after the 2:1 ratio and 5K bonuses.
Then booked BA award travel via Qantas since they are/were OW partners.
I was fortunate enough to have flown her by this method in 2002. Did BA First on a 747 over, and Concorde back. Could have done both, but the departure/arrival times worked out better and I'm glad to have experienced BA First, too.