I haven't forgotten about it. I'm still thinking about it. But I have a bunch of projects I'm working on, and (much to my delight) another one has come to the forefront recently. But I want to post an update on where that other mystery idea stands, and I will as soon as I have a development.
In other news, this mystery project is, well, a mystery. Not that I really have to worry about it, but I don't want to say anything about it until it's ready.