Using Intel HD 3000 graphics card, is it possible to combine the bandwidth of a single link DVI-D and HDMI (using an adapter?) and support a monitor with resolution 2560x1600 monitor instead of 2 1920x1200 monitors?
First, the reverse:
A single connector with a dual-link DVI port usually drives a single display. It is not capable of getting split in two and driving two independent low resolution displays.
You can use extra hardware to clone the signal and drive two monitors (with identical contents on the screen) or you can use extra hardware like the (now older) Matrox dualhead2go's
Both options require extra hardware.
However, assuming such hardware exists:
PS: If you do search the web, do not get confused with the DMS59 connector, you can not use that 'reversed' to solve you problem. Even though it looks a lot like DVI.