Customization of  splash screen of your RCP / IDE application :

In RCP / IDE application splash screen is created by extending "org.eclipse.ui.splashHandlers". this extension allow to contribute custom splash screen during start-up.

 3 type of existing template for splash screen available ( An Interactive Splash, A Browser Splash, An Extensible Splash )

i would prefer using product configuration file.once you select particular customize splash  template , it will extend the extension and create necessary code for the customize splash screen.

For more product customization please refere :
http://eclipse4rcp.blogspot.com/2010/12/product-customization-using.html