Why not use a RasPi? Can run 24/7 on less power and uses UTP/Linux...
My actual rig is is written up here. Though the blade has been replaced by 2 rockminers. Those rockminers have been sitting idle for 4 months
TL;DR: The RasPi has only 256MB or RAM. That is not really enough to run a full Bitcoin/P2Pool/namecoin node. Together those use at least 1.2GB of RAM on my machine. I am also not sure of the CPU capabilities of the RasPi. Lately P2Pool has been using 40% of one core. I am interested in replacing that machine with something a little less power-hungry though.
I am also going to need moar disk-space soon too. I have only 10GiB left on a 50GiB partition (left 4GiB for swap, 4GiB slack (because: SSD is "not for server use"))
Good point, in your setup a RasPi would not make sense...
But for Firewire2013 (using the standalone S3's) who uses the laptop for remote access only... I would recommend a RasPi... (Cheaper, runs 27/7 on Linux).