Alas I probably cannot get this list (I was too optimistic there), since the driver for most of my stuff is sMerit and deranked  Jr. Members had no merit at the time. Upgrading are on the other hand detectable, since they move from 0 to 1 or above sMerits… sorry for getting hopes up there …

The way to get the list would be really:
a)   The obvious easy way would be to ask @Theymos, who may or may not release it in full.

b)   Even trying to do the task from a snapshot (*) would not be 100% accurate. Say for example a Jr. was deranked on the first day, but ranked back up on the second day. Both the snapshot and the current database would state the user a Jr. Member, since he ranked back up between both database instances.

(*) Getting a proper full DB snapshot is really in the hands of a few even so. @Vod has higher chances (if he has a complete DB backup from the date the change was performed, but reparsing the whole database is done every couple of weeks I think, so those demoted and re-ranked would not be captured as I stated above.