Update: that panel was actually produced by BOE themselves, at the company's Gen-8 AMOLED pilot line in Hefei
It turns out that BOE had a 55" UHD (3840x2160) WRGB OLED TV prototype on display at SID 2014. The TV features a contrast ratio of over 100,000:1, a color gamut over 85%, a response time of 0.2 ms and a brightness of 120-400 nits. The whole TV is less than 5 mm thick.
It seems likely that BOE is using a 55" 4K panel made by LGD. After all we know that LG already launched such 4K OLEDs in Korea, and the Korean company is happy to offer its panels to other makers (including Changhong, Skyworth and perhaps even Sony and Panasonic).
On the other hand, BOE is not a TV maker - they produce panels for other makers. So I'm not sure if it makes sense for BOE to show a prototype using a panel made by LGD. The largest AMOLED panel produced by BOE (as far as I know) is a 30" FHD panel shown in 2013. While BOE is advancing quickly towards AMOLED mass production.
BOE is also actively developing flexible AMOLEDs and ink-jet printing technologies. But of course it's likely that the company's first commercial panels will be small rigid AMOLEDs for mobile phones and perhaps wearables as well.
Comments
The whole TV set and panel are designed and made by BOE.
I think the panel was fabed by BOE.