NewEgg has the FIC Falcon CR51, a super small barebones system based on the Mini-itx format. This is great as a thin client, Linux web server or kid's PC. I will set mine up with a wireless NIC and flash drive for a super quiet workstation. The best price I can find elsewhere is $160 + $25 shipping. Some of the NewEgg specifications are lacking detail so I've inserted notes below.
FIC Falcon CR51 Small Form Factor Bare Bones PC
Chipset: VIA Apllo PLE 133 & VT8235 [Via Epia Series]
Processor: VIA C3 EBGA processor series [933Mhz]
System Memory: 168 pin DIMM memory sockets X 2, 512MB max [1 GB Total]
Audio: AC' 97 Codec onboard
Video: Embedded in PLE 133
USB: 1.1 X 4
Bays: 3.5' HDD X 1 CD-ROM X 1
Networking: 10/100 Mbps Fast Ethernet
Power Supply: 150W Flex with PFC
Expansions: Low Profile PCI X 1
Form Factor: Mini-ITX
Dimension: 294.5 X 135 X 260mm [10.24"(D) x 5.31"(W) x 11.75"(H)]
FIC Falcon CR51 Small Form Factor Bare Bones PC
Chipset: VIA Apllo PLE 133 & VT8235 [Via Epia Series]
Processor: VIA C3 EBGA processor series [933Mhz]
System Memory: 168 pin DIMM memory sockets X 2, 512MB max [1 GB Total]
Audio: AC' 97 Codec onboard
Video: Embedded in PLE 133
USB: 1.1 X 4
Bays: 3.5' HDD X 1 CD-ROM X 1
Networking: 10/100 Mbps Fast Ethernet
Power Supply: 150W Flex with PFC
Expansions: Low Profile PCI X 1
Form Factor: Mini-ITX
Dimension: 294.5 X 135 X 260mm [10.24"(D) x 5.31"(W) x 11.75"(H)]