I wish I could help more, but I don't have a sample. I know that it can be done because I've seen it done and I did it myself about a year and a half ago, but I don't have those files anymore. The best I can do is give you some clues. If you work it out, maybe you can post the solution in more detail.
Okay, let's see what else I can remember about how to do this. Say you have two forms - let's call them the "source" PDF and the "destination" PDF.
1) Enter the data into the "source" PDF
2) Click a button to "share" the data with another PDF
3) On that "share" button's click event, take the information you want to share (possibly the entire data DOM as XML) and store it in a global variable. Global variables exist outside of the form - they are in the host (i.e. Reader or Acrobat). To be clear, I'm referring to the Global object, which is part of the Acrobat scripting model. See the documentation at
http://www.adobe.com/devnet/acrobat/pdfs/js_api_reference.pdf.
3) After parking the data you want to share, open the "destination" PDF using app.openDoc. Again, this is from the Acrobat scripting model, not the LiveCycle model.
4) On form ready of the "destination" PDF, access the global variable that the other form created and read in the data.
For kicks I had a quick glance at the newest (version 8) documentation for Acrobat JavaScript. It seems that there are some new security restrictions surrounding the use of the global object, which may throw a wrench. So I'll take back my "I know it works" statement and replace it with "I know it used to work".
Hope this helps.
Jared Langdon
www.jlangdon.ca