Of late I've been trying to find pre-printed examples of 48 sheet posters from the 70s and 80s in N/2mm scale as I don't have a printer to produce my own. 48 sheet posters (with an aspect ratio of 2:1) were very popular then and apparently are still the most popular size for outdoor billboard poster adverts in the UK. Unfortunately most commercially available N gauge landscape posters are not the correct 48 sheet poster aspect ratio. And believe me I've looked at a lot of ranges and companies.
Consequently I've taken to producing some myself (and arranged for a friend to print me a sheet). Unfortunately it is very difficult and time consuming to find suitable images that are square on, without trees, lampposts, shadows etc., across them, of period 48 sheet posters. I've also made up a few and they're not all for the period I want, but here's what I've managed to collate so far:
And here's a quick snap of what they look like (except the spock/heineken one which was a commercial one from Sankey Scenics - I was rather disappointed as the ebay ad showing it mentioned that others posters were included in the pack but none of those were 48 sheet posters and most were small portrait format posters).