Hetzner pre-provisions systems. If you're a existing customer in good standing and don't have special wishes (e.g. you don't enter something in the "comment" field of the order) your system will be ready in ~5-10 minutes.

They build their own PXE setup and assemble the hardware themselves. iirc they have >100.000 physical servers on 2 locations. Each location consists of ~10 buildings like described here: http://www.datacenterpark.de/images/rz_modell.gif

Here is a screenshot from BING maps (link doesnt work): http://i.imgur.com/6zNvBz1.jpg

Here are more official details about their data centers: http://wiki.hetzner.de/index.php/Rechenzentren_und_Anbindung...