Amazon US still has green mid-pro...

https://www.amazon.com/dp/B08LY3F4SJ

Edit to add: It's being discussed in a few other posts, but it's highly unlikely that Drop will restock the rev6 plancks. They've been talking about rev7 for nearly a year, so with the supply chain the way it is, it makes far more sense to put efforts into getting a new revision into production than a previous revision. But also due to the supply chain problems, it's impossible to predict how long it will be.