I guess I have my answer. I tried one of the boards and it appears the DVI-I is not dual-link which limits the resolution. Hopefully it can be added with a bios update and won't require a new board revision. So 1920x1200 is probably the maximum digital resolution.
If you have a monitor requiring a dual link you'll probabably only get a maximum of 1280x800 as I did with my Dell 30" monitor.
Still, there is no way the 2560x1600 resolution is correct for analog vga.