I will order one of these and make an image for it:  https://www.newegg.com/Product/Product.aspx?Item=N82E16813128975

I understand why members are hesitant to try a USB key, cheap USBs are usually terrible: and fast ones are usually expensive. 

The Lexar drives I recommend are both fast and cheap.  Other members have requested I fully support SSDs again; so I am going to re-add full support for them in a later version. 

Currently you will either need to use manual intervention or make some changes to the system or bash files when using an ssd.

Personally I use all Lexar 16gb USBs with my rigs; except one has a Lexar 32gb I got to test.  I think they are the better choice over a more expensive ssd.

This is my reasoning:

The 16gb Lexar's I recommend are very fast (watch one of the nvOC demo videos if you don't believe me)

are very cheap: $8

are easy to attach to image then remove and reattach to a rig

vs a regular SSD or HDD allow you to use at least one less cable on your rig.

Finally using a usb key allows users to try nvOC without needing to install over their previous OS (no commitment needed).

Although one could use a sata to usb adapter with an ssd, or an type of usb ssd / adapter (there are a lot)  and it would match all the advantages other than cost.  I recommend spending $8 on a Lexar 16gb and seeing if it is fast enough for you; if it is (and most likely it is) then you just saved ~$30 per rig.