Dual link DVI or DisplayPort definately support 2560x1440, I don't think HDMI does.
FYI:
WA - 1 x Dual Link DVI-D [HDCP], 1 x HDMI, 2 x VGA
WB - 1 x Dual Link DVI-D
WC - 1 x Dual Link DVI-D
WD - 1 x Dual Link DVI-D [HDCP], 1x DisplayPort, 2 x HDMI, 1 x VGA
OcUK sell the WC and WD screens.