I'm no expert, but, in case no one else is, either, my understanding is that DVI handshakes between the source and monitor, so you couldn't have two monitors showing the same thing. In addition, while a DVI can be "dual-link", I don't believe that that means it can control two monitors, only double the bandwidth to one monitor. However, since DVI can carry both digital and analog signals, it's possible that the Y cable splits the digital and analog signals to separate cables. Of course, if that's the case, you're no better off than using the VGA cable. I'd be curious to know the exact set of pins on all three connectors on the Y cable.

It just occurred to me that Bruno probably is an expert on this sort of stuff. Ah, well. I've already typed it in.