Since time does not permit me to write in more extent, just a short note: yesterday, I have published a Gentoo Bugzilla bug assignment UserJS. When enabled, it automatically tries to find package names in bug summary, fetches maintainers for them (from packages.g.o) and displays them in a table with quick assignment/CC checkboxes.
Note that it’s still early work. If you find any bugs, please let me know. Patches will be welcome too. And some redesign, since it looks pretty bad, standard Bugzilla style applied to plain HTML.