Okay, here are my two cents:
First, why hasn't any intrepid journalist found some Alabama and/or Texas national guard members who actually served from 1972 to 1973, and asked them to release their records? That way, we could compare what's supposed to be in the files, (i.e., what duty the guard actually recorded, how complete the records were for other guardsmen, etc.) with what Bush says is in the files. As a federal employee, I just don't buy that the records are as sparse as the administration implies.
Second, the tenacity of this fight indictates that the Bush administration isn't trying to hide Bush's attendance record. It's something totally different. Could it be that our favorite 22 year old alcoholic fratboy did something embarassing while in the guard? Drug use, sexual misplay (don't ask, don't tell?), or some other fratboy prank? THAT's where the story is, and it will come out.