You can flatten all the fields before merging the files. Of course, then
you won't be able to edit them anymore...
The resulting form still would still need to be editable.
Then you'll have to edit the names of the fields before merging the files,
which is not an easy task.
Basically, you can either do it manually, or with a script, but the latter
will remove any formatting, validation or calculation scripts that are
associated with the fields.
A script sounds great, where would I begin? Is there a way to add a leading string to each field name ("Text3" could become "Form1_Text3")?