If you can't find a seat on DL, it may be worth a call to SkyMiles and ask about availability on Air Europa. They fly MIA-MAD and JFK-MAD. Those are options that won't show up on the online search. Air Europa is pricing about in the low-mid $2K range to paid J.

Here's a picture of the cabin on the A300.

http://www.airliners.net/photo/Air-E...202/1066448/M/