as title says, the project successfully builds and loading screen pops up of the game, however it immediately then goes into a white screen. the build settings have all the proper scenes set up and the game runs in editor as well as expected.
The problem had resolved itself after clearing cache from xcode and rebooting both the iphone and the mac then rebuilding the project.
Haven't seen this particular behavior, but here a few things to try when you get odd launch behavior.
Check the debugger console for any error messages. (When a level loads in the editor but not on the actual device it can mean you are running out of memory, for instance.) http://answers.unity3d.com/questions/16791/iphone-log-files
Might also be worth deleting the build off your device, then rebuilding your target from scratch. In rare cases that has been known to help.
Also try rebooting your device. It's less common now I think, but it used to be that odd app behavior could happen as memory got scarce on the iOS device. I still see app pages on the App Store that suggest rebooting if you install their app and it doesn't work at first.
Did you generate a terrain in your project?
I had the same problem and it was because I had a terrain in my project. Unity iOS does not support terrains, so removing the terrain fixed the problem.