Something new surfaced in the T-Mobile Project Dark rumor mill. TmoNews (via BGR) published what is supposed to be a leaked T-Mobile ad that is related to Project Dark aka Project Black.
The Ad has two big arrows with the text Even More and Even More Plus. "It also says Coverage you need Price you want & The Handset you Crave". The last line says: "Most Affordable Unlimited Rate Plans".
This would all point to the currently favored interpretation that T-Mobile Project Dark means an all-you-can eat plan possibly priced at $50 per month.
Since there is Even More Plus, I assume the $50 plan will have a caveat and you actually want that Even More Plus, which will then be more expensive again.
Either way. T-Mobile managed to generate a lot of hype around Project Dark. Not even the Sidekick data loss disaster could stop it.