We do not have an omnibus collection for Ms. Carmody's works scheduled at this time. We currently have 'The Rebellion' scheduled for release in November of this year and 'The Dreamtrails' scheduled for March of next year. 'The Sending' is tentatively scheduled for release in July of next year.
All editions currently available for purchase or pre-order (through 'The Dreamtrails') for U.S. residents can be found here: ~Link~
and for Canadian residents can be found here:
~Link~
'The Rebellion' has the cover of Ashling, so it looks like it's Ashling + The Keeping Place.
'The Dreamtrails' has The Stone Key cover, so it looks like it'll be The Stone Key + Wavesong (finally, how it was intended to be read, as one book!).
The Sending they have said isn't going to be released until July, and that this date is still tentative/subject to change makes me wonder if they're releasing it as The Sending at it's original size. They certainly couldn't be releasing it with The Red Queen - it'd be far too big.
I don't know where these ~Link~ editions are coming from. I've contacted Book Depository this morning in an attempt to get an answer. It looks like the Random House edition, both from the cover they're using and the fact they're calling it Book 7, but if it is I have no idea where they've plucked that availability date from.
Your best bet is to try get a hold of one that's advertising that it's Book 6 and that it's got the Australian cover, that's over 750 pages, otherwise you may have a long wait.
QBD do international shipping: ~Link~
And a member located this site to buy from: ~Link~
I'll let you know when (/if) Book Depository get back to me about which version they're selling.