The Prodtest videos were produced here in the States by an associate of mine. These tested carts are currently available in the US.
Here is a link to one of these videos:
Most sync carts are using the USB boards manufactured by Cambrionix, a UK company. To my knowledge, they are the first "non Apple" USB boards that were developed.
The most secure carts are only available in the States, manufatured by Datamation. They use a heavier gauge steel body, drill proof locks, and heavy duty hinges. They are generally lower in price than imported carts and other manufacturer's in the States.
I have not seen the new and improved Ergotron doors, so I cannot comment at this time. When I first viewed them in 2011, I told the rep that the doors were poorly constructed. Their response was not positive.
John J Caprice / Visualedtech