No, but you can create a UIViewController that has just a UIImageView (the same splashscreen image used by the application) that you can use to "simulate" a longer initialization time.
When data are retrieve, you can simply pop it from the stack and initialize your real UIViewController.
The only problem is to retrieve the correct image from your device: the launch image does it automatically, I suggest to implement a simple methods to choice the correct one so you will avoid any problem.
Here is an answer to detect if you are on iPad, iPhone 4" or iPhone 3,5".
You can use it to select the correct image and use it on your UIImageView.
I use it in my applications and you won't notice the difference.