I have seen a lot of questions on this topic, but no answers. So I thought I would share my experience here.
I currently have a WDTV live with 3 external drives connected to it – two 4 TB drives and a 6 TB drive. AND I am only using one of the two ports on the WDTV live.
The trick is this – WDTV cannot support multiple drives because it cannot power them, so a simple hub extender is useless. BUT, Walmart sells a 7 port hub that plugs into a wall outlet. I think it is about $35 bucks. I have my drives plugged into that and the hub is plugged into the back port on the WDTV live. The front port is still open, so … who knows? I might be able to get 14 drives hooked to it.
I have been running the two 4TB drives into the hub with the hub connected to the WDTV for a long time – over a year. I just added the 6TB drive. I loaded a few things onto it because I didn’t know if a drive that large would work. I had to reformat it to NTFS, was the only gotcha. After the reformat, I added a few files onto it and plugged it into my 7 port hub. WDTV accessed it fine.
Sometimes you just have to have that hacker mentality.