I've thought about making an eink calendar before, but since the cost is so high I wondered if it would be cheaper just buy 31 2 inch screens and somehow connect them.
Since our software allows tiling we've built some test large scale composite screens out of our 6" and 9" devices - I think maximum was around 25-50 screens combined in a big virtual surface, with resolution over 10k x 10k pixels. So sure, it can be done, but is a pain to setup and run.