The developer usernames are tied to the wiki usernames (code_authors table in mediawikiwiki db), and the wiki usernames have associated emails.
It should be possible to CC or assign a bug to a svn username and get 'the right thing done', either by translating to an username only at sending time or at the first stage when translating (that would disclose emails, but since that is for developers, that should be usbscribed in bugzilla, seems ok).
Version: unspecified
Severity: enhancement