MLU and Exposure Delay w/VRI 70-200 on D2X Question

This is a 100% crop of a shot I took yesterday using the D2X on a heavy tripod, with mirror lock-up and exposure delay. I wasn't zooming. This is at 70mm. The flag is 250 yards away. I shot this at f/7.1 @ 1/600. I bumped up the ISO to 200 just 'in case'.

I have not sharpened this in PS. I just lightened it up when I opened it in ACR. I shot this in numerous ways, ISO 100, stopped down more, etc. Little diff.

Is this the best I can get from this camera and lens? Is there anything else I can do to get the image sharper?

I haven't found a way. I have been shooting with this camera and lens six years and still feel at 100% like I'm missing something. I just had Nikon service this lens to be sure it wasn't that. I rarely print anything like this 100% crop. 50% is my max. But maybe I'm just ignorant and missing something.

Please try not to rip me too badly guys. I am just trying to improve. It's been a long week. Thanks for any feedback.

P.S. I'm including a 72 dpi full shot that the crop was taken from. I lightened it up (again) before saving the jpeg. This full size shot is what I would normally use for print publication....