I am newbie for iOS development. What I have done so far is as below.
You have no code used so far, but you'll absolutely have to do that to achieve this. I'll get you started:
Create a scrollview at the bottom of your viewcontroller. Create UIViews on it and make them have a width of 640 (iPhone Retina screen width). You can put a image and a title on the UIView and make them function as a button. Set the content size to 640/4 *7 and there you go. You can give the background of the scrollview the same image as the UITabBar, but you'll need this.
This snippet might help you:
for (int i = 0; i<7; i++){
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0 + 50*i,0, 50,50);
[scrollView addSubview:view];
}
You'll have to multiply the x origin with the width of the UIViews (plus some margin) to make sure they aren't all on the same spot.
EDIT :
I think this one may be even more adapted to the situation. Contrary to KLHorizontalSelect, it's kind of old (no commit on the master branch for a year ?) and I have no experience with it, but it may solve your problem : InfiniTabBar.
The description is short :
A scrolling tab bar with space for infinite items
Maybe you can take a look at this control : KLHorizontalSelect.
Here's how it looks like :
I don't think it looks exactly as you want, but I think it works almost as what you're expecting. Maybe you can work on the design ?