I know I can use the apple-mobile-web-app-status-bar-style meta tag and after adding the web page to the home screen, it will run the app in full screen mode.
My question is if there is any tag, css or javascript I can use to tell mobile safari to do it directly, without having the user adding to the home screen first?
You could consider something like PhoneGap that deploys a webapp as a native iphone application. It would also allow you access to things like the accelerometer via javascript calls.
There is a way of automatically installing 'webclips' on your idevice. You do this by deploying a profile payload to your device (.mobileconfig file).
Payloads can be signed or unsigned, for testing purpose unsigned profiles will come up as Insecure.
The advantage using a profile like this is that you can set it so the user cannot remove the 'webclip' in the standard way, having to remove the profile to remove the app. You can also protect this with a PIN.
One reason I didn't use this method for registering my apps was that I couldn't get it working offline with appcache manifests (iOS6.x), however this may have improved since iOS7.x
