No, Dual-link DVI is a single output, a single cable but it puts twice the "grunt" through to the monitor than a regular DVI connection. You need all that power to push 2560x1600 on the 30" display. Currently there is no method of plugging more than one display into the MBP. There are solutions for the PowerBook that involve a PCMCIA card.
It's pretty likely an ExpressCard version will be made as it would be able to access the much faster PCIe bus but whether the adapter will be the 34mm version found in the MBP or the 54mm version is as yet unknown.