For the America West A320 look at Project Airbus (http://www.avsim.com/projectairbus).  The plane is made for FS2002, but I have it working in FS2004.  Sometimes the files cannot be downloaded from their sight, but they are all posted on the Avsim server.  There was a very good MD-88 made by SGA.  Look over at Delta Virtual (http://www.simairline.net/delta/md88.html).  They have all three versions of the colors.  My personal favorite 757 is ProjectOpensky's (http://www.projectopensky.com).  On their site they have Northwest's newest colors.  If you are looking for the older paint, search here.  I hope these help.

Mike