the option to search for a minimum size for the file we are looking for is already present in kazaalite.in your case do the following:
1. type for monster in the search bar
2. select the video option below it
3. select "more search options"
4. tick the "size" box
5. in the 2 drop down menus that appear select "at least" in the left one and "400 MB" in the right one & then click search.
you can use the search filter to exclude "monsters inc." from ur results just type the word "inc." in the box provided.be sure to remove it after ur search is complete.
coming back to the topic, searching for file types on the basis of extension wud b a great idea.