Those look like various IBM redundant PSU. At least 1460 watts, I'd say. FYI you can get 2000 watt bladecenter PSU on ebay pretty cheap! ($60 or less).
See this thread:https://bitcointalk.org/index.php?topic=212431.0
Looks like he's using a small cheap PSU to power the MB, and a LARGE server PSU he's adapter for PCIe cables to power the GPUs. In that thread, I suggested a similar setup would be pretty cheap to implement (rather than buying some big ass 1500 or 1600W PSUs.