(Updated with talk of $50 unlimited plan) T-Mobile's mysterious Project Black may be a combination of the company's phones and a rapid expansion of its fastest 3G service, a quick follow-up source said Friday. Rather than center on a specific device or a plan, Black would on pushing T-Mobile's upcoming high-end phones, including the Behold II, Bold 2 and Cliq, and matching them with the quick deployment of its 21Mbps HSPA+ network throughout the US. The timetable and the specific plans are still unknown by BGR and others.