@cayars: Thanks for your opinion. I do like to tinker, but I would like to know if this would work. Also, what is the cheapest computer that can run Emby on then?
What you have to understand is that a typical cluster of PIs like an Octi can't just run anything you want to run on them. You need to be able to take the tasks and break them down into small parts that can be worked in individually. Then 1 PI could work on each part in sequence or 2 PI can do the same work in roughly half the time. 4 PIs in 1/4 the time, etc BUT this requires having access to the code to break down functionality into these small parts that can be handed out.
Emby is NOT written to do this as such.
The cheapest computer you could use is something you already have around the house or something a friend/family isn't using and can donate to the cause (maybe in exchange for access?).
Make no mistake, a low end PC can be used if you are careful with the file types you use with it BUT the more powerful the better.
If you don't mind spending $150 then an Android Shield TV can be purchased new which will can be used as both a SERVER and CLIENT assuming you have external USB drives or storage on the network where the media is stored. You would need this even if going the PI route. Shield TV has both wifi and Gb NIC installed and has on board GPU to help with transcoding (on the fly conversion of media).
The Shield TV isn't perfect (but getting close) and would still allow you to "tinker" but that can be said with any Emby install.