To make mod notes a tiny bit easier to see and find, we've added Staff badges, like the ones currently used in MetaTalk, to MetaFilter and Ask MetaFilter. [more inside]
We just added (staff) markers in the bylines here in MetaTalk if the commenter is a mod. [more inside]
Suggestion for a small format change: how about putting the byline on top of the comment in discussion threads? This would allow us to efficiently skip comments from users we don't want to hear from without resorting to user killfiles, and without wasting precious seconds of I'm-surfing-at-work-and-I-really-shouldn't-be-doing-this time to realize that this is a comment from that guy. Having the byline at the top would save a bit of scrolling and skimming, since you'd know what you're getting into right from the start. Also, some MeFites are "must-reads" for me and I'd like to make sure I don't blow past them.