Yes, there’s a limit which is partially due to WP and partially due to PHP itself.
You can see more here: http://wordpress.stackexchange.com/questions/96587/menu-items-disappearing
As a user of websites, I would say that 100+ items in the main navigation bar is a bit overkill. Perhaps try linking out all of the pages inside Footer widgets, and only keeping super important items in the main menu?
Of course, if you increase some of the variables mentioned in the post above, you should be able to add more menu items 🙂