Observations:

Could have made the case longer and still fit in the rack. A longer case would be about enough room for 10 miners with fans on each row. 40 miners total.
Each power supply is more than enough to power 10 miners dual mining and one 10 port USB hub.
Case has enough room to fit 5 power supplies and about 5 USB hubs.

I will not be building this up further as newer (much) more powerful rack mountable scrypt miners are soon to be released. These 5 chip gridseed miners are too much of a pain to wire up and rack.