I guess it can accept up to 2 Billion characters (virtually unlimited). That is about the Max but how would you fit them on a regular page?
If you set the page to flow and to expand to fit size.
I had a user send me a form that had a very large response to 1 question. Every time I would scroll to that point I would get a failure message and the form would shut down. I was able to abstract the text and copy it into a word document. It filled 30 pages of text in the word document.
I'm not sure if this was caused by the size of the response or possibly there was too much information to fit into memory on my computer. The original form was 5 pages long when the form was filled in by the user it was 96 pages long.
When I tried to export the data to xml the process came back incomplete.
So this got me wondering if there was a maximum size limitation.