Did you search in the FileExchange already?
- http://www.mathworks.com/matlabcentral/fileexchange/41624-newfile
- http://www.mathworks.com/matlabcentral/fileexchange/4908-m-file-header-template
- http://www.mathworks.com/matlabcentral/fileexchange/27132-automatic-template-for-new-functions
- http://www.mathworks.com/matlabcentral/fileexchange/27865-creating-function-files-with-a-header-template
- and many others.