You might try Revell directly. They do sell decals sometimes if they have extra in stock (let me know if they do!!). For what you are looking for, try the email first. Monogram separated from Revell in 2006, but it is worth a try as I can't find an address for Monogram anymore.
Revell, Inc.
1850 Howard St. Unit "A"
Elk Grove Village, IL 60007
Phone: 1-800-833-3570
Email: cservice@revell.com
Or you may want to try: http://www3.revell.com/catalog/catalog/Parts-11-1.html
Did you see this reference? Thought it might be helpful: http://www.swannysmodels.com/B17G.html
I've built four of the 1/48 Monogram B-17G's, including two of the ProModeler kits. Sorry, don't have any decals left or I'd have scanned them for you.
Good luck!
On the bench: Academy 1/72 B-17G 'Blue Hen Chick'; 1/48 Tamiya Mustang III; Kitty Hawk 1/32 P-39.
Completed: 1/48 Tamiya P-51D Mustang - 'Show Bird', 1/32 Dragon P-51D Flying Tigers 'What if'; 1/32 Tamiya P-51D Big Beautiful Doll
Group build:1/48 Tamiya Mustang III; 1/48 Tamiya P-51D Show Bird
