Dickies Men’s Deluxe Long Sleeve Coveralls – 7.5 oz Twill Mechanic Jumpsuit with Zipper Front Industrial Uniform Fit

You could look into cotton twill grey coveralls by brands like Dickies (example) or Kolossus (example) These suits don’t have all the pockets and details of the original suits. The do have diagonal zipper’d front pockets which I think is key. They’d be suitable if color is your primary interest, I think.