Slightly OT: there is now a wing tip mod for the MD-80 series out there, apparently:
http://www.airliners.net/photo/Jetran-Air/McDonnell-Douglas-MD-82/1075139/L/
http://www.airliners.net/photo/Jetran-Air/McDonnell-Douglas-MD-82/1088763/L/
The same airframe before modification for comparison:
http://www.airliners.net/photo/Jetran-Air/McDonnell-Douglas-MD-82/1051746/L/