If you would like to customize the date text in iOS 7’s Notification Center, you should check out NC Date Customizer – a new Cydia tweak ( available for free via BigBoss repo ). The tweak will allow you to configure the text to your liking as seen in the screenshots above.
The tweak comes with a dedicated menu in the Settings.app where you can enable/disable the tweak. You will also be able to force the text to display in a single line as opposed to the default two line display. The configuration menu also gives you a RGB slider and an alpha slider for picking the color that you wish your date text to be in. And, you can also choose how opaque or transparent you want the text to be.
Also, NC Date Customizer is open source, and you can get the source code on GitHub here.