The main/only issue[1] that I see with it right now is:
- At least 20 points (see below)
Each person gets N points whenever they are trusted by someone, and loses N points whenever they are distrusted by someone, where N = 0 if the rater is less than a full member and N = [rater's activity]/120 if the rater is at least a full member. The 60 people with the highest scores are selected, this list is randomly sorted with a higher weight given to people with higher scores, and the top 30 people in the resulting list are suggested.
This could be gamed by account farmers : a) For their benefit, i.e. that their accounts show up. b) To remove someone from showing up.
Also, instead of hard-forcing people to set trust as I described there, I think I'd instead have the trust link be red on every person, saying something like "Warning: you need to set your trust list!".
Sounds good/less intrusive.
[1] Although I'm not sure about the long term impact that it will have on fighting scams and other shady behavior. I mean, if the system gets slowly gamed (as mentioned above) this situation eventually gets more and more enforced. The more often someone shows up on there, the more likely it is that they are going to get included by someone else and the cycle repeats.
Additionally you should make it so that it does not show the people that you have already in your list (to avoid somewhat newer members from getting confused).