First off, reds8n has this gem over on Dakka:
Playtesting etc is well and truly finished.
Book is at the printers.
Next up is the fact that for years now, the entire range has been Direct Order only (remember that, there will be a test later)
We have heard that several product codes have recently been pulled, making them unavailable for retailers. This is usually a 90-120 day sign of updated product coming down the pipe. We are working on more details, but most of the products aside from the expected Spearhead ones (like the Fire Prism) are Witchhunters and Daemonhunters sets. These are not products being pulled back to direct order, but pulled altogether.
So lets look at the overall schedule and what we think is going on:
May: Orks&Goblins WFB
June: Spearhead 40K
Fantasy 8th and the next 40K codex have got to be shoved in there fairly soon after Spearhead I would think. The conventional wisdom says that for 40k, we will see a fall and holiday-january release slots for the next 2 books.
So at this point we have word of product be readied for replacement that would correlate with a possible GreyKnights/Inquisition release in the August-ish timeframe, and word that the Dark Eldar are at the printers. Note however that the Dark Eldar are direct only now, so there are no products to pull, and Games Workshop could simply reintroduce them at will.
~So here we sit. Standard caveats apply, but it would seem that it is now almost certain that the next two 40k Codices will be Dark Eldar and Grey Knights/Inquisition. The real question is which is first in the late summer timeframe. The jury is apprently still out on that one. In any case, your morsels and thoughts are welcome. I for one am already dreaming of the nail in coffin of the whole WH/DH cross-codex Imperial unit borrowing. That fix alone would help the game tremendously.