Over at the chibi-san date Livejournal community, zeittari posted that Chibi-san date was once again missing from this month's issue of Comic Birz. The strip has apparently been on hiatus for a few months now, and mochironnai posted that "it is said that if you don't have good ratings then you get cut by the tenth month."
Chibi-san Date went on hiatus after chapter 10.
Now I don't think Tokyopop would have licensed the manga for an English release were this the case... but you never know. Maybe Himaruya is swamped with another project (Hetalia Volume 4 maybe?).
Original Livejournal Post: http://community.livejournal.com/chibisan_date/11042.html