Another Imperial Armour book at Forgeworld is being worked on, and this weekend might reveal some clues to it. What we do know though, is that it will have Tyranids in it.
Please remember that this is a rumor. Perhaps some options for Lords of War would be very cool.
via a reader on Faeit 212
I asked forge worlds about their current imperial armor book for tyranids, they said an up date is due in a few months along side a brand new imperial armor book for tyranids