I think the physical description of these devices has been done to death elsewhere, so I'll just put up my photos.
As ever, hi-res versions in images.
Overview
Components - connecting board is just a pass through, except when there is power on both sides, when they are connected via a via. :-) The connector itslef is a standard PCI x4 connector.
Main board Top
Main Board - Bottom
Board 2 - this contains all the power regulators, the major connectors, and the 2nd Chrontel DVI chip.
Board 2 - Bottom