T-Mobile 'everything unlimited' plan to offer voice, SMS, MMS, data for $50?

A new rumor has emerged that T-Mobile is planning to offer an 'everything unlimited' plan that will include unlimited voice, SMS, MMS and data for $50.

BoyGeniusReport details the plan, internally nicknamed "Project Dark." That report attests that it's a multi-pronged assault, rolling out the RIM BlackBerry 9700, Motorola CLIQ and Samsung Behold II on the hardware side and a "very, very rapid expansion" of T-Mobile’s 3G network on the service side.

"We don’t mean UMTS," BGR's Marc Flores writes. "We're talking 21Mbps HSPA, the same as what just launched in the Philadelphia market."

An unnamed source says the pièce de résistance is a $50 unlimited plan that includes voice, SMS, MMS and data.

Why so low? It's "meant to represent T-Mobile’s new strategy...try and poach [subscriptions] from various low-cost carriers," Flores writes.

I'm not so sure this works out in the long term. The cost of mobile service has only risen over the years, and while I do expect there to be heated competition in this space, it's much easier to drop the one-time prices on handsets than give up recurring income.

Certainly, there's been increased interest in the prepaid arena (Boost Mobile, MetroStar PCS, etc.). But unless T-Mobile is banking on a small customer base, it seems like it's not a sustainable plan.

What do you think?