Here is one more release schedule from a source that has a different, but a very close connection to Games Workshop.
via another anonymous source
Games Workshop is aiming for an army book/codex every month. Its high elves, eldar, apocalypse, lizard men, marines then tyranids. I'm just not sure of the months and whether marines are October or November and what was in between marines and tyranids.
This is a separate source than what we had heard from earlier this morning. I had not checked my inbox yet, when the earlier post went live, but it seems to confirm that we are indeed going to see eldar very very soon.
Attaching this rumor set to months would look like this.
High Elves- May
Lizard Men- August
then September+ looks like it gets a little vague. Could we see both Space Marines and Tyranids this year?
Also this seems to correlate with Hastings release order.