Given that I had already looked into it (about 3 months ago) and there seems to be tremendous interest in fastai TPU support, I can restart these efforts in the coming weeks then. I had run out of GCP credits but I should be able to get access soon.
Here is the repository with my (messy) work. I will update this repository with my progress as I dive back into this project during these upcoming weeks (just waiting to get funding for GCP use).