Is there a limit to the size of a production file being generated with a variable data file?

There is not a single number as there are variable conditions that will have an effect. For example, large vdp runs (data merging from an uploaded xls or csv file) can sometimes fail, especially when there are lots of image fields and/or the master PDF is huge and/or the output is being imposed. 
We performed a test to determine the work capacity of eDoc, loading a vdp file with 200K rows and 4 columns (text only, no images, and no impositions). 
As a result, eDocBuilder processed 800K records in total. The production file was generated as expected (after a reasonable time).
Please Note: The test was performed to push the tool's technical capabilities to the limit, so please also consider our EULA section 8A about the policies concerning the fair and reasonable use of Service resources.