I've discovered that the Dux Bellorum release date is now showing as 21 August 2012.
Osprey Publishing now have it up on most of the national Amazon sites at a pre-order discount (around a tenner in the UK, for example). Now, I'd prefer people to order from their local games shop or local independent bookshop if you're lucky to have either, but Amazon seems to be the biggie to order from (cheaper, too, but those extra couple of quid at your local book/games store will help keep it going).
Presumably the cover showing on Amazon is a finalised one ... When I have that confirmed I'll get it uploaded here too.