Selection of chassis/ cabinet/ case and PSU when assembling a custom server

Selection of chassis/ cabinet/ case and PSU when assembling a custom server

I am planning to assemble servers with primary objective of
virtualization. Currently the first machine I wish to set up is tower
server with following configuration:
Processor Intel® Xeon® Processor E5-2620 95W x 2
Heat Sink Intel Heat Sink AUPSRCBTP x 2
Mother Board Intel® Server Board S2600CP2 Form Factor SSI EEB 12" x 13"
135W x 1
RAM Kingston 64 GB 1.5V ECC Registered DDR3 KVR16R11D4K4/64 26.4W x 4
HDD Seagate Constellation ES ST1000NM0011 1 TB 7.4W x 4
Now, I am unable to find enough guidance online for selection of Cabinet
and PSU.
Starting with PSU, I am doing a rough calculation based on max power
consumption of each component like 95W x 2 + 135W x 1 + 26.4W x 4 + 7.4W x
4 which comes to roughly 460W and assuming additional power required by
CPU and Cabinet Fans I think a 500W-550W PSU should be sufficient for this
configuration. I want to know if this calculation is correct or I am
missing something important that should be added to the calculation ?
Apart from this, for the motherboard do I need something specific to SSI
EEB boards like special power connectors etc ?
Going ahead to chassis/ cabinet/ case, I am unable to find any enclosure
that includes SSI EEB 12" x 13" board natively and most of them need
drilling few extra holes to make EATX cabinet compatible for SSI EEB form
factor. How can I overcome this problem ?
I have also gone through Intel Server System
http://ark.intel.com/products/56412/Intel-Server-System-P4308CP4MHEN but I
don't know if there is any point in spending extra $200-250 because the
same configuration can be assembled. Any plus points for this Intel Server
System over assembled counterparts ?
As of now, I have selected following Enclosure and PSU:
Cooler Master HAF X
Cooler Master Silent Pro M600
Both of the above mentioned components are quite expensive so it would be
really nice if someone can suggest any cheaper alternative and if possible
something that has the looks of cooler master HAF series as I am not
interested in rack mounting the servers.