Thats a great idea. I believe titleboxing.com and possible boxinggalore.com have fightposters. Just search fight posters and many sites have them for sale. You can also go to
HBO: Boxing and go to their download section and download fighter posters from the last 3 yeras and print them out using gloss paper on your printer and they come out extrmeley nice. Thats what I do. I have a complete room full of fight posters with my collection.