Asking $900 OBO -  will accept BTC/MtGox USD/Paypal at current exchange rate.
Please PM ALL offers!
Selling my Quad 6870 GPU bitcoin mining rig.
Put into production on May 23rd 2011 in air-conditioned/climate controlled datacenter.
Runs like a Dream, no issues.
Ships with Ubuntu 10.10 and poclbm.py  -ready to mine out of the box
Never Overclocked, though cards support several options.

Rig at stock clockspeed does 1100-1200 M/hash on deepbit
 
Cost $1500+ to build in parts alone

Have done 1 deal on #bitcoin-otc
Also have stellar ebay feeback: http://myworld.ebay.com/tomatosauce

Specs are as follows.

GPUs:
4x ATI Saphire Extreme 6870
1024 MB/1050  Mhz Mem clockspeed
900 Mhz Core clockspeed
PCI Express 2.0 x16

MOTHERBOARD:
MSI AM3 USB 3.0 + Sata 6GB

PSU:
Cooler Master Silent Pro M100 1000W PSU

CPU:
Quadcore AMD Phenom II X4 955  Black Edition 3.2 Ghz

Memory:
Patriot Memory 'Sector 5' G Series 4GB

Case:
COOLER MASTER HAF 932 Advanced RC-932-KKN5-GP Black Steel ATX Full Tower

HD:
IMATION SATA2 64GB SSD (pretty nice)