Jack did a great series on build a MDF buck for his Caddy project. It's embedded in this thread and is addressed in post 430 through 494. It starts on page 43. A really good tutorial on how to build a quality buck.
http://allmetalshaping.com/showthread.php?t=14068
Here is a link to page 43. The buck portion starts at the bottom of the page.
http://allmetalshaping.com/showthrea...=14068&page=43