I don't know how you knew I was JUST looking at this question (I know I'm always behind, been a tough week). Actually, yes, it IS possible. I'm putting it on my TODO list to provide the the code / info needed to do so. It's tough trying to balance time into getting the new, nicely wrapped stuff working versus sharing / explaining the hacky solutions used for testing. Basically it involves installing the sz tool, which on OSX is just:
brew install lrzsz
It allows you to transfer a file using the ymodem protocol (which is how the Choosatron accepts a story file). There are a few other bytes to need to prepend in order to appease the Choosatron (to tell it you plan on sending a story, the position in the list of stories, file size...). So that exists. There is getting a compiled Choosatron story binary of course, which can be done from a Twine source file with some gross Python scripts I have (without getting into the writing app).
Of course, the OTHER way to deal with this, is (once you have a compiled story file) putting your story on an SD card inside the Choosatron. If you hold down button '2' on boot it will look to the SD card instead of internal memory. You can also flip an internal flag to change the default (whether it looks at internal memory or the SD card UNLESS you hold '2'). This is easy to set with a CURL command.
So, I can get the python scripts / examples uploaded for you to generate story binaries in the meantime (this won't take me much time at all). Then, depending on what you would prefer in the short term, I can get a tutorial up for transferring a story over serial, or a tutorial on using the SD card slot. Any preference on where I put that time?