<p>I have a friend using a small HD monitor. He is pretty happy with it.</p>
<p>https://www.smallhd.com/</p>
<p>B&H has a large selection of on and off camera monitors with SDI and other pro inputs.</p>
<p>http://www.bhphotovideo.com/c/browse/Monitors-Accessories/ci/1844/N/4028759523</p>