I have seen hugelkulture beds in "city garden tours" and they seem to be thriving and doing well. The aren't super tall, but I think scale is relative to location.
I'm going to attach a picture of the logs I'm putting under the end of my
berm to build out a hugelkulture bed on the tip.
The bottom is going to be logs, second layer leaves and evergreen boughs from
yard waste collected around the neighborhood, and the third layer (top for now) is going to be wood chips.
... Not sure where to find that much dirt, but we're still digging in other parts of the yard, so we'll see. Hope I don't have to buy it...