You need to read through this..
http://en.wikipedia.org/wiki/Digital_Visual_Interface
Get to this point
"
Example display modes (dual link):
QXGA (2,048 × 1,536) @ 75 Hz with GTF blanking (2 × 170 MHz)
HDTV (1,920 × 1,080) @ 85 Hz with GTF blanking (2 × 126 MHz)
WUXGA (1,920 × 1,200) @ 120 Hz with CVT-RB blanking (2 x 154 MHz)
WQXGA (2,560 × 1,600) @ 60 Hz with GTF blanking (2 × 174 MHz) (30-inch or 762-millimetre Apple, Dell, Gateway, HP, NEC, Quinux, and Samsung LCDs)
WQXGA (2,560 × 1,600) @ 60 Hz with CVT-RB blanking (2 × 135 MHz) (30-inch or 762-millimetre Apple, Dell, Gateway, HP, NEC, Quinux, and Samsung LCDs)
WQXGA (2,560 × 1,600) @ 60 Hz with CVT-RB blanking (269 MHz) (This is for high end monitors when operating at greater than 24 bits per pixel.)
WQUXGA (3,840 × 2,400) @ 33 Hz with GTF blanking (2 × 159 MHz)
"
Here's another point
"Dual link maximum data rate is limited only by the bandwidth limits of the copper the DVI cable is constructed of and by the DVI signal's source."
And then the whole thing depends on the quality of the copper wire used.....
Here are a few cables that will give you the required refresh rates
http://www.monoprice.com/Product?c_id=102&cp_id=10209&cs_id=1020902&p_id=2408&seq=1&format=2
http://www.monoprice.com/Product?c_id=102&cp_id=10209&cs_id=1020901&p_id=2686&seq=1&format=2