A few weeks ago my brother was asking me how to get several TV's in his house (he's renting out to several others in a large sub-divided house) to be able to view movies from a common NAS box. And how to do it as cheaply as possible.
So I showed him what I did: Took an old laptop (Celeron dual core with 1GB RAM and 200GB HDD of which screen was broken) installed Lubuntu on it and plugged its HDMI into the TV with a wireless keyboard & mouse. Thus actually have a full-on PC from my couch to the TV. Used the LAN port to the router and linked XBMC to read the media files from the NAS/Server/other PC's/laptops. Worked a charm with no hiccups - could even browse web if I wanted to.
Well, at the time my suggestion was: Get a small cheap / second hand PC and install a Linux (or the like) on it. Then install XBMC, AFAICT the absolute nicest media manager ever. Or to make it even more simple, install OpenELEC which is a Linux with XBMC pre-installed for you with all needed drivers and ancillary services to make it work nicely with stuff like remotes, and it starts directly into XBMC. I even suggested to him to look at something like a Raspberry Pi, since OpenELEC has made specific versions for just that platform - but he's not too happy with trying his hand on such "technical finicky stuff".
So doing a bit more research, it seems that many pre-made set-top boxes are in fact just that: A Pi (or similar ARM "PC") with something like OpenELEC installed. Many of these are even below $100 on Amazon, so I'd expect them not to be much more than R2000 here (possibly even less). Then I found this nifty guy (: Pivos XIOS, and reading through that I saw it's using Android as its operating system with their own brand of media player. So I thought ... couldn't you actually use an old android phone for this?
Lo and behold, XBMC themselves has just made a version which installs on Android as an APP! http://xbmc.org/xbmc-for-android/
So now: the only "extras" to buy would be a way of linking the microUSB port on the phone to a charger + HDMI for the TV. Then the phone itself would already have wireless LAN capabilities, that might need a bit of work as wireless has never been a good idea for me - don't know is an adapter on the USB hub might allow for a wired LAN. And then it might only need a remote (if possible). Anyone know of something which might work for this?
Edit: just browsing some more ... came across this thing: Even better: http://www.amazon.com/Dual-Core-Smar...&keywords=xbmc
For $80 you get something which simply plugs into the TV's HDMI port (no other wires involved) with Android 4.2 and XBMC already installed. Only gripe may be the wireless LAN, would look at a USB-to-LAN adapter, for the remote I can actually use my Android phone!