The coronaLabs tutorial for text editing (a notepad like app I think) is at:
http://www.coronalabs.com/blog/2012/02/07/tutorial-text-input-with-native-ui/
I did a quick look in the code exchange and didn’t see any helper code / libraries, and a quick web search too. Kinda surprised no one has made a good text entry module yet.
In general the chatter I hear from most devs is that they don’t use multiple native.textfields onscreen at once due to various issues/complications.
More typically, standard display objects are used for display / initial tap detection, and then either a single native field is created on top of it for the input, or the native field is created off screen and the input mimicked to the standard display.newText field. When enter is tapped, the native field is typically destroyed and the app continues on without the side effect of having a native field onscreen (always on top of other objects).