I made a dynamic PDF-form in Adobe Live Cycle which has 4 pages.
On each page there are 16 similar rows, each rows contains 3 different elements.
The first element is a text field, the second element is a Drop Down Menu and the third element is an EAN13-Barcode.
Once the user entered a valid code and ".exit" the text field the DropDown-Menu gets updated and only has specific choices depending on the value of the text field:
if(this.rawValue == "9H23")
if(this.rawValue == "xyz1")
EAN.rawValue = "1234567891011";
It might be a bit low tech, but i use in-form storage for some forms i have done. I have hidden text fields and built a dialog for updating the textfields within. I never need to modify the actual form in livecycle, i just save new information into it as needed.