Is it possible to send a predefined SMS or MMS or Mail with a predefined text ?
As of now, it is not possible.
A way to get around this, however, is to make a text area and tell the user to copy the text, click on a button opening an empty sms (Ti.Platform.openURL("sms:_");), and then pasting.
That's, as far as I'm concerned, the only way to do such thing.
SMS / MMS - Nope. Not programmatically possible with Titanium. I'm hoping that 1.5.0 will give us the ability to, but I'm not too sure :(
Email - Yep. Simply use the EmailDialog API.