Some years ago, I suggested that the shadowmap be editable for those with more-powerful systems. The result, thank you MS, was the drop-down box that permits increases to the shadowmap up to 4096.
Of course, that was years ago and now I have a GTX 880M in my laptop, with 8Gb of video RAM. :-) Any chance you could add more options in that list? Say, up to 32,768?
Alternatively, is there an .ini file I could edit directly?