I am trying to create a NAS but I want to run my own software on it. I want to be able to download data around 20MB/s over WiFi from the system.I used a raspi and created a prototype, but as it uses a single bus it is not able to transfer data from the HDD to the user at the rates I am talking about. Anybody know any build that suits this? Looking for suggestions.Budget – around USD 300 - 400Size requirements – as small as possibleOperating conditions – Will be deployed in my van: take impacts into consideration, I am planning to devise a case that can solve this issue.  Needs heat dissipation solution as my van is not air conditioned. Desired software you want to run on it – web server running on Node.JSStorage media – 2TB HDD (as of now I use a 1TB external)Power solution – need a powerbackup that can last for one hourI need good network adapters and USB ports that won't hinder my data streaming. Dust proof as I am installing this in India where dust and temperature are a common phenomenaI don't need a screen.I want the case to be smaller in size, I am willing to fabricate one myself if its needed to address my needs. 
MediaCenter with through put of 20MB/s
nas