The website and reference to exoslot, which was created before it was actually on the market, suggests that up to 8 lanes can be connected to each transmitter unit, so that if you have 4 of these you can run up to 32 lanes.
Not the case. Each 'deck of cards' sized transmitter unit accepts cabling (DS300/DS200 cables) for up to 4 lanes.
Still, it's a pretty slick unit, really.