Is there a Backbone style PHP library?

Is there a Backbone style PHP library?

I need to write some Models and Controllers in PHP with similar
functionality of those in Backbone.js. I wonder if there is a similar
lightweight Backbone style library for PHP, providing similar classes and
methods. I've looked at several PHP frameworks but could not find any
lightweight one that compactly fits into a file or so. It seems the
frameworks are mostly concerned with things like routing, HTML rendering,
DB access, which are, in my case, either not needed or trivial. The
non-trivial part is creating a modular structure with Backbone/Underscore
- like functionality. Of course, I can rewrite the pieces of Backbone code
into PHP but I feel a bit like re-inventing the wheel doing it.
To make it sound less vague, the exact tasks I am looking into are PHP
cron jobs that download files, unzip them, parse line by line, filter and
validate, then generate collections and save them in a database. The file
are quite large, so I cannot just upload them into memory, manipulate, and
dump into DB. I have to use cache collections that are being emptied and
exported as memory gets ful.
I would assume those task are pretty generic and useful for many other
projects, which is why I am asking this question here. Many thanks for
your help!