In MySQL, is it possible to get more than 1024 characters back from GROUP_CONCAT

You need to set group_concat_max_len to a higher value. This can be done on a session or global level. The following query sets the max length to 10,000 for the rest of the queries in that session:

SET SESSION group_concat_max_len = 10000;

What you’re running into is the group_concat default max of 1024.