I did not build the CAPS2 design. I kind of made my own design mainly focusing on getting a completely fanless design that at least had the option of upgrading to include the SOtM tX-USB and SOtM In-Line SATA Power Noise Filters (I did not include them in the initial build primarily for cost reasons). I am not sure how much difference these add-ins will make in the end since the Nova Pre has galvanically isolated digital inputs.
In the end, I decided on the Intel DN2800MT motherboard and M350 Universal Mini-ITX enclosure from mini-box.com. I used 4GB of Crucial RAM and a Crucial SSD (just 64GB, but that holds pretty much all of my roughly 100 CDs ripped to level 4 flac). I added an Intel half-mini pcie wireless card and pigtail/antenna since my available ethernet sockets are nowhere near the location of the computer. I also used a recommended 60 watt AC-DC power adapter. Throw in a copy of Windows 7 Home Premium, JRiver, JRemote, External DVD Drive for installing Windows, and a keyboard (I didn't have one - though I did have a mouse), and the total cost is about $575.
Future upgrade possibilities include the SOtM USB and/or Power Filter in addition to a second SSD. I am considering an mSATA drive since the cable management in the tiny case is already a bit of an issue -- I want plenty of air flowing through there. I'm honestly not sure the SOtM power filter will actually fit with the way the SSD is mounted (the connectors are very near the front panel of the case already); also, using an mSATA drive would rule out the SOtM USB as an option.
As for the Nova Pre, I am really happy with it. As subtle as audio differences usually are, it is definitely a reasonably significant improvement over my 11 year old Marantz SR-7000 HT Receiver (I was only using it as a DAC/Stereo Preamp). It just sounds a bit "cleaner" to me -- one might say it "does silence really well" (which is to say, I am really impressed by how there seems to be absolutely no background noise).
If I had one complaint about it, it would be that the output voltage is too high (for my Classe CA-101 and B&W CM1 at least). I continually must dance around 9:00 on the volume control, a region where the control seems to be more sensitive. I got a pair of Harrison Labs 12 dB attenuators which have helped with this issue a bit.
EDIT: I should mention that I am a bit proud of my little audio server since it is the first computer I built from scratch (I used to do a bit of repair). I am really excited that everything went along without a hitch.