I'm not sure what's going on with the towers mentioned in the article, but a related concern that I've heard next to nothing about (and nothing at all as far as a security concern) are the network extender devices that are available, such as:
What is the Verizon Wireless Network Extender?
The Network Extender enhances indoor calling and 3G data coverage to provide better service for your Verizon Wireless mobile device. It’s an extension of our network placed directly in your house or small business office. The Network Extender is compatible with all Verizon Wireless devices and works like a miniature tower. It plugs into your existing high-speed Internet connection to communicate with the Verizon Wireless network, which makes it easy to install.
These things are essentially small network towers with limited range and capacity that plug into an internet connection. The intended use is for when you have poor cell coverage at your home, you can get one of these things and your cell phone will see it as a tower and the cell communication will be routed over your internet connection. As far as your cell phone is concerned, it's just another tower that it's connecting to.
So say a black hat gets one of these - now they can see all traffic between the extender unit and the internet. Presumably that traffic is encrypted (though I haven't seen anything from the vendors that explicitly say that), but how often have we seen such embedded encryption be done in a way that can be cracked?
Also, since the unit is relatively cheap (a couple hundred dollars?), an enthusiast is very likely to be interested in tearing one down - who knows how easy or difficult it might be for them to tap into something that leaks information before it's routed to the internet?
Anyway, some food for thought. I don't think you need access to an actual cell tower to have some (or even a lot) of the capability that the article hints at.
Actually, after a quick search, here's a white paper that seems to describe just this sort of attack: