I came 697th out of 25,000 .... not bad I suppose. (Actually, 697th out of the men, so that's a bit less impressive).
Here is a link to nice little video montage of the 2007 Tokyo Marathon. Near the top of the page are three links to the video. The wma one started but then produced an error for me. I got the Quicktime one to work. It definitely gives you a great sense of the scale of the event.
I'm going to post my splits and a few thoughts on my race in the next day or two. I have been very busy at work this week.