This is interesting. Like many people, we have, in the past, spent a lot of time browsing car boots and eBay for vintage dress patterns, ideally in unopened condition. You would guess Simplicity have realised this happens and jumped in with the Simplicity Retro range.
From what we can gather, these are vintage patterns reproduced for the modern market, with the packaging showing the original images and in some cases, updated versions too. All you have to do is get the cloth and get cutting and sewing.
Annoyingly, there isn't a section on the maker's site or the John Lewis site (which also stocks them) for the retro patterns, so you'll just have to look through and try to find the patterns from the 1940s to the 1960s. On the plus side, they aren't expensive, all selling for just over £4 each.