Hey!
Ellipsis mode isn't a thing in STM but there is a feature that should work like linked overflow! Check out the sample scene on "pagination". Basically you can link two STM objects together, so that text will automatically overflow from one to the next, respecting active tags and read timing. This can chain as many STM objects together as you need.
Ellipsis mode sounds interesting, though... I might be able to implement it in the same way hyphens are tossed in automatically. I'll write it down!