the checkin you mention seems unrelated to me.

we use this feature in svn heavily at work, in fact ticket numbers are required for checkins, and its very convenient. the idea is a history of the files changed to fix a particular issue. even if you have to back out the change you can see the activity in the ticket and know its related.

a plugin would be fine too. im not going to tell you how to implement something, its just a suggestion.