You heard correctly. I'm rolling around again with one more new Super Emerald today. It could be released at any time, so you'll just have to keep refreshing the forum home page until you see it!
As for the teaser:
Every challenge up until this point was either a brand-new or revived old challenge. This one is a hybrid of sorts. I have taken an old challenge (You know which one I'm talking about if you remember the proper order last time) and made a slight modification to the conditionals to make it harder than ever.