Hi Eugene,
Expanding the prefix beyond 10 characters sounds like a good idea, but it would be a significant change. We'd have to take the entire database offline and rebuild it.
As for using it in the headline, this is up for discussion. Some disadvantages:
* Everyone who presumed it wouldn't be so prominent before would now find that it is. For example, I have "Mr." as my prefix, but I'd rather not see Mr. Chris Whitten as the headline of my profile.
* This will hurt "cousin bait" SEO. If someone is searching for Stephen Harper they're probably using "Stephen Harper" as the keywords. The headline is important for this matching. If we put "Right Honorouble Stephen Harper" in the headline it's less likely to be found in a search for "Stephen Harper."
As for it helping when looking for matches, what do you mean?