So, back to the idea: it's not easy to go on the trust "tree" and pinpoint the possible weak links = people who most probably you would not actually trust, but they are trusted (also indirectly) by people added to your trust list.
Aren't you just looking for your
Trust list - Hierarchical view?
I've also made
Personal Full Trust Depth viewer for all users a year ago, and last updated it half a year ago. I'm currently running an update, if my script still works it will probably take 2 days to generate a few GB of data.
Update:
update done!
Trust lists quickly get very big because of this:
Custom Trust lists have large recursive implications because the users you trust directly (Depth 0) make you trust the ones they trust (Depth 1), and the users they trust (Depth 2)