Greys are not to Browns as Greens are to Blues, but Greys are to Clears what Greens are to Blues. Something like that!
On pretty much all Cherry boards with Clears you should find a Grey beneath the spacebar.
However, the only difference between Grey and Clear stems seems to be the colour. I've tried Greys with springs from Clears and korean 65g springs, and they feel the same as Clears with the same spring. The tactile slide thing looked exactly the same if I recall correctly.
I'd only recommend a keyboard with only Greys to people with really manly hands. I tried using Greys everywhere on my Phantom for a while, and boy, that was heavy. I think Clears are a bit too heavy though, so it wasn't that surprising. If you've used Clears and thought "man, these are for girls", then a Grey keyboard is probably the way to go. Others should be warned though. :>
By the way, a spring from a black switch is a lot lighter than one from a grey switch, and the construction of Browns isn't a lot like the one of Greys or Clears, so that wouldn't make a good "try before you buy".
Nah, I'll wait for Ducky G2 PRO DK9008 w/ MX Super Black.