The Discussion Forum forum management max char limit for a post is 99999. Is it possible to significantly increase this?
I think you need to hack the core files to make this change. Look in the theme or module files for the specific field that you want to change. Without knowing which field you want to adjust, I can't point you to a specific file. You can remove the character limit instead of increasing it to make it unlimited.
You may also need to adjust the string type of db column where the data is stored to accommodate the larger data. MEDIUMTEXT will store 16,777,215 bytes or ~16MB of data and should do the trick for you. This can be accomplished through a tool like phpmyadmin which your web host most likely supports. This video shows you how to change the type setting in phpmyadmin... NOTE: You will need to identify the correct database column... the one in this video is not what you should change, it just shows you how to change it.