This is a nice little clip of Geoff Duke explaining how he came up with the idea for one-piece leathers in the early 1950s, recruiting his local tailor in St Helens and a ballet outfitters in London to shave fractions of a second off his lap times:
…and here’s a black one-piece leather suit worn in a slightly different way by Ms Faithful in 1968:
Motorcycle Memories 
Aha, you’ll be wanting to read “With an Eagle on the Back” Jonathan Boorstein’s treatise on the black leather jacket in the forthcoming issue of The Rider’s Digest.