I've seen even higher scores on the PS3 version. About the only way to top them is to get nearly 100% of the kills on Shibuya alone. I believe the max score possible is about 66200. I made #2 on the 360 boards, but couldn't find the interest to do another run.

If you want to make a run on Invasion this weekend, I should be available if I know ahead of time when you want to start.