[How To] Give a few "trusted" members option to bump any thread.
I personally like this concept quite a bit. There have been cases where I've wanted to bump threads without posting in them or using the announcement tool. That said, I wouldn't let my non-staff members use this plugin due to potential abuse.
Since roles are additive.
1) you could create a new role called Bumpers.
2) go to permissions for the bumper role and give that role ONLY this permission (nothing else checked anywhere).
Plugins manage Bump Discussions X
3) add a few users (e.g. Bob, Joe) that you trust to the Bumper Role (e.g. that are in the Role Member)
4) edit the Users Bob and Joe and add the Bumper Role to those two users.
5) So now Joe and Bob are in two roles Members and Bumpers (therefore they have the privileges of Member Role with the privileges of Bumper role as well.
I may not provide the completed solution you might desire, but I do try to provide honest suggestions to help you solve your issue.