Well, to get something specifically for that year, you'll probably need to get a Gillette of some kind, since I don't think many others have date codes. Taking a look a the ShaveWiki date code chart, you can just go across the chart for 1956...
Your choices would be the Tech and Blue tip (mild), Red tip (more aggressive), and Flair tip (regular) SuperSpeeds.
In terms of variants of those, I suspose there would likely be small handled travel sets for the Tech. I'm not familiar enough with the SuperSpeeds to know any more about what kind of special cases, or sets those might have come in for that year. Most all Gillettes you'll run across are brass, with some sort of plating. The blue tip has an aluminum handle, however.