It was officially declared few months ago by Nokia, that Symbian Belle would be available fourth quarter onwards for S^3 range of devices which came in the very first S^3 batch. Probably fourth quarter stays up-to 31st December. With the presence of Stable and latest leaked version of Symbian Belle (111.030.0607) for Nokia N8, we can assume that its somewhere in the corner.
Another clue is that
Nokia Singapore website which was previously showing: (Symbian Belle will soon be available as a software update for these handsets: Nokia X7 and Nokia E6) has been updated with Nokia N8, E7 and 500. So its the time, Nokia is preparing their regional websites for the official launch of Symbian Belle for old range of S^3 devices.
Update:
Nokia Russia website shows that (Symbian Belle will soon be available as a software update for these handsets: Nokia C7, Nokia N8, Nokia C6-01, Nokia E6, Nokia 500). It seems that these Nokia web site managers are too lazy to put all the names of S^3 devices which will get the Belle update, the Nokia Singapore website had missed Nokia C6-01 and Nokia C7 from the list of devices which will receive the update, while Nokia Russia website has missed Nokia X7 and E7.
Keeping in view the above situation, we can say that Symbian Belle would arrive for all S^3 devices pretty soon. (Thanks for the tip Bananajo)
