As David Hayden pointed out to me, I should be able to implement ITitleAspect on any of my parts in order to control how it's displayed in the dashboard (see
my post as well as
his post on the matter).
However, I can't seem to get it to work unless I either:
a) create a contenthandler that sets the metadata.DisplayText, or
b) change the implementation of the TitlePartHandler (by casting the content item to an ITitleAspect instead of an TitlePart)
Is this a bug in the TitlePartHandler, or am I misunderstanding how ITitlePart works?