These are in stock, tested and ready to go.  Grade B:

QTY: 2 - HP Z800 12-Core - 2x E5645, 8GB, 160GB SSD, DVDRW, W7P COA, FX1800+
QTY: 4 - HP Z800 12-Core - 2x E5645, 8GB, 160GB, DVDRW, W7P COA, FX1800+
QTY: 8 - HP Z800 8 Core - 2x E5620, 64GB, 160GB, DVDRW, W7P COA, FX1800+
QTY: 8 - HP Z800 CTO - NO CPU, NO RAM, NO HD
QTY: 1 - HP Z600 - X5550, 6GB, 160GB, DVDRW, W7P COA
QTY:  1 - Dell T7500 8 Core - 2x X5667, 24GB, 500GB, DVDRW, W7P COA, FX3800
QTY: 2 - Dell T7500 8 Core - 2x E5504, 4GB, 300GB, DVDRW, W7P COA, , FX1800+
QTY: 5 - Dell T3500 - W3503, 4GB, NO HD, 160GB, DVDRW, W7P COA, , FX1800+

$4900 obo takes all.