Matt,
Here is a thread with pics and the dimensions, look like a good place to start
http://www.rcuniverse.com/forum/m_14...tm.htm#1426055
or here under plans and drawings
http://webpages.charter.net/rcfu/
And a really good one I just found [X(]
http://www.rcbay.net/Downloads/MagnumFieldBox.zip