I was browsing through the ModMyi forums and found a SMS Vibration 3.0 Fix by a user by the name of WaLLy3K.

You can download a copy of the SystemSoundVibrationPatterns.plist and read more about it after the jump.

Now what this will do is change the vibration settings to:

Email will be 1 vibrate (default)
Calls will be long constant vibrate (default)
SMS will be 3 short vibrations

The SMS vibration will be the default 1 vibrate if you are in the SMS application.

Installation:

SSH to the following folder: /System/Library/PrivateFrameworks/Celestial.framework/
Make a backup of SystemSoundVibrationPatterns.plist (I renamed mine .bak)
Download the SystemSoundVibrationPatterns.plist and copy it to /System/Library/PrivateFrameworks/Celestial.framework/
Restart your device!

I hope you enjoy your new vibration, and thanks to WaLLy3K for making it.