RIPE Atlas using XPort Pro
The RIPE Atlas project appear to be using (at least for the prototype) an XPORT Pro as a very lightweight, widely distributed performance monitoring network.
The XPORT Pro is essentially a programmable, USB-powered ethernet interface with brains, and formed the basis of the Botanicalls Twitter circuit for talking plants. This is a really very interesting mass monitoring system, giving extremely low-overhead performance measurements, which means the uptake will be much higher than a rack-mounted power-hungry black box.
Find out more at: http://labs.ripe.net/atlas