A year or so ago I read an article saying that the IUPAC was going to make a change to the atomic masses listed on the periodic table with a dozen elements being listed with ranges of average atomic mass depending on the isotopic abundance. When I initially read the article, I went hunting a poster with the new masses but had no luck.
This past week, however, I finally found the 'finished' product which has some spectacular visuals showing the relative abundances of the isotopes.
From what I can tell, however, the poster isn't available for sale yet. There is a pdf (or here), and I found an older (August 2010) presentation from the IUPAC detailing the plan for the poster/digital product and a much newer article
Now I need to see if that pdf is a larger enough file to get good resolution if printed (in color, of course) really big - like 36" by 24" - because I WANT/NEED this on my classroom walls.