Well, they've been dropping some nice and subtle hints about it on their mainpage.
THINGS TO LOOK FORWARD TO IN 2008
"Okay, I lied. Except for the fact that 2008 will likely be Kotonoha’s farewell year, there is really nothing much to look forward to from us in the next twelve months. We will be doing the same things we already did last year and the year before that. In our defense, it’s kind of hard to come up with something new and innovative to do when you’ve been so long in this “business.” I wonder if it’s too late for us to switch to the Shōnen Jump route… ;)
Anyway, the good news is we’re not dead yet! Which means you can still expect a few more releases from us [...]"