> klesterjr [...] developed an excellent AOS4-theme for MOS that i'd love to see released
> one of these days.

Just to add that there has already an OS4 theme been released for MorphOS, by another author:

https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=8568&forum=3&start=3
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=8888&forum=3&start=14