I've also wished there were a way to transfer from AmEx to EB, but haven't found a method with a reasonable exchange value yet.

However, if your AmEx is issued in the U.S., you can transfer AmEx points to U.S. Airways who are a Star Alliance member. Then have U.S. Airways book your Star Alliance reward on SK.

Of course, this is not useful if you wanted to use the points for upgrades on SK instead of full rewards tickets.

I also wouldn't do it until you are ready to book an award and can confirm availability through U.S. Air. But I did check on it once, via AmEx Travel Service, and they actually could get me an SK flight using points via US Air. They were willing to hold the ticket for a few days to get the points transferred over (I ended up not taking it, as plans changed, but at least it was an option).

Susan