Ashley could it be possible?
It's really important but missing feature when you creating custom text input fields.
You have Text object displaying a content of the input from Textbox.
And it's fine, whatever you write in text box will show up in Text object.
You can even emulate cursor at the end of the text with a sprite.
But things go nasty when pressing left/right arrows. Cursor position will change in Text box, but not in the Text object. And if you start writing again, text in Text object will appear somewhere in the middle while sprite cursor standing still behind last letter :)
Found this page http://snipplr.com/view/5144/getset-cursor-in-html-textarea/ maybe usefull.