Talking about "cutely-colored site contamination maps", this seems to be the most recent one available still:
Tepco published it on Aug 2, 2011.
At the joint U1/2 stack near unit 1 the yellow label says "70~100" (mSv/h). On a large bubble off to the left it says "U1/2 SGTS >10,000".
I think the pictures were taken towards the west, as you see the slope behind. Also, there's a small damaged two storey structure behind the stack. This is visible inside the stack frame on the west on aerial shots from the south on Cryptome.
The vertical brown-stained pipe is probably connected to one of the two smaller pipes that run along the fat pipe from the Y-section leading to units 1 and 2. There's one at each side of the fat pipe.
Ian Goddard speculates on his site that the brownish colour is not rust but cesium. However, for that the pipe would have to be leaky, for you to see cesium condensate on the outside, not just the inside.