A more direct Cython layer between PuLP and CBC. PuLP-CBC supports callbacks.
$ sudo apt-get install coinor-libosi-dev coinor-libcoinutils-dev coinor-libclp-dev coinor-libcbc-dev coinor-libcgl-dev libblas-dev liblapack-dev libbz2-dev
$ git clone https://github.com/danielfullmer/pulpcbc.git
$ cd pulpcbc
$ pip install -r requirements.txt
$ python setup.py build
$ python setup.py install