The London Lounge

The old Minnis Rangoon book comes to mind. There was a charcoal melange. A great mixture of colors that resulted in a, well, mélange effect. Or what some might call "heathered." The old Gilt Edge book featured a medium grey melange, and the Lesser SFT book included an RAF Blue mélange. Any other sources?

Samuel,
I'm not sure what kind of cloth you're looking for. Just a mélange of colors?
For instance, would a grainy Fresco work for you? John Hardy has a nice 13 oz. mélange in grey. Or a Smith's smoother texture fresco in a grey/blue mélange?

Not easy to describe. One knows it when one sees it. There are frescos that feature a mélange look. Shades of white and grey woven into the cloth, alongside the primary (gray, navy, etc.) color. The Rangoon charcoal melange is an example, as is an old Gilt Edge gray. So many of the better known panama solids do not feature any variation of color.

I was asking about the kind of cloth because I think that you could easily get your desired "mélange with many of the Donegals or Cheviots. For instance the Multi flecks from Magee of Donegal or the Moss or Blue-green from Lovat.
Of course these are heavier and you mentioned Panamas......