You can do this by embedding your tab bar controller in a custom container controller. You can do this in a storyboard by making a UIViewController the initial view controller, and adding a container view to it. Size that container view so it has whatever space you need underneath, and add your view in that space. Delete the view controller that comes automatically embedded in the container view, and control drag from the container view to your tab bar controller, and choose "embed".
Be aware that there's a bug in the way tab bar controllers layout their views in iOS 7. If you put a view near the bottom of one of the controllers, it will appear the first time you see it, but move down under the tab bar when you select another tab and then come back again (it will reappear if you rotate to landscape and then back again). You can get around this bug by making your container view controller (the initial controller in my storyboard) the delegate of the tab bar controller, and adding this code.
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { // called by the embed segue
UITabBarController *tbc = segue.destinationViewController;
tbc.delegate = self;
}
-(void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
[tabBarController.view setNeedsLayout];
}