maisdesign

It disable Post editor for Non Administrators and let you create posts only using Custom Fields (remember to configure them first!) 
It uses: if ( ! current_user_can( ‘install_plugins’ ) )
Actually there is no Admin Panel for this plugin if you would like to change minimum permission or role you’ll have to change it manually via FTP
<h3>Feature Request</h3>
Any feature request? Drop me a line: marco@maisdesign.it
This plugin is based on a conversation here: 
<a href="http://wordpress.stackexchange.com/questions/45113/how-to-disable-edit-post-and-allow-only-custom-field/45158#45158" rel="nofollow ugc">WordPress.Stackexchange</a>

Editor Remove

It disable default Post Editor and let users like Authors and Editors (not Admin) to write posts only using custom fields.

Editor Remove vs Advanced Custom Fields: Extended