I follow what Adam of PF is doing and would like to post more A7/R first tests and news! ;-p
The following article is really worth a look, it is unique as there are various full samples posted including a complete ISO series:
http://www.eprice.com.hk/dc/talk/1433/3951/1/
(for A7, in Chinese)
Well, while noise is really low at high ISO speeds, I am afraid that the noise reduction applied is too strong, causing too much detail loss as a result. As for the A7R, ISO test crops are posted in the following:
http://www.dcfever.com/sony/readnews.php?f=1&id=9212
(for A7R, in Chinese)
It can be seen that the loss of details is even worse! It seems that the strong NR kicks in from ISO 1600 and upward. So, 36MP might still be too many the pixels for a 135 Full Frame sensor!
Besides, I am not quite impressed with the skin tone and the colour rendition in general. It's surely a Sony that can be easily seen, of which the style and taste are well known to me, whom is also a Sony user! :-)