In the process of creating my own panel, I have found some great sites that I thought would be helpful for anyone else interested:

http://home.att.net/~sfinger/products.htm

http://www.simpits.org/database/graphics/737-800_panels/737_panel1.html

http://www.flyingzone.co.uk/index.html

http://www.b737.org.uk/aircraftsystems.htm

http://www.artietheairplane.com/main.html

http://www.tech.purdue.edu/at/courses/at262/

http://www.gecas.com

http://www.sasflightops.com/gallery/A321/A321_01.htm