I am not sure we have a fixed date yet. I acutally was meant to do some things I didn't get to because I was a bit busy off Zenphoto. We did delay it because of that and other things that needed fixing.
You can already preview what is coming/planned:
http://www.zenphoto.org/news/zenphoto-1.4.6
You also can try the build from the development stream to have the theme ready when it is released:
https://github.com/zenphoto/zenphoto/tree/1.4.6 (you can switch branches on the top left)
Click on "Download zip" on the bottom right.
The theme entry has been added:
http://www.zenphoto.org/theme/zpbase/index-gallery.jpg.html
@gjr: I saw you made your own function for the page . ZP now has one built in already you might want to look at `get/printHeadTitle()`(The latter prints also. Actually it is indeed inspired by the one your used for your other themes as well, though not exactly the same in details.