Actually, this isn't tilt-shifting: using the same principles, I tried to replicate the Holga effect here. Clear in the center, blurry and darkened on the outside, and one more blur-over for luck. With a little more work it could look almost the same.
Just an outdoors shot of Nicollet Mall. I'll try it out with Holidazzle some time.
I think it's important to get a picture at least four floors above ground level for these shots. People and objects really need to appear tiny, and the perspective needs to look down from above upon the landscape. Too acute of an angle and the effect is lost, so I think.