Items that don't get enough votes to diffinitively tell whether they're approved or unapproved after a certain "long" period of time could be an issue. One way to handle this could be to automatically flag it for moderator review some how. Or, there could be some kind of "reward" system that could grant points to people that vote up or down an item like this; that would give the community incentive to vote for these stale items.
Talking about incentive, I guess there would have to be some kind of point reward for those that spend a lot of time reviewing and voting (up or down) for items too. It shouldn't be too many points for voting, but it should definitely count as community participation.
As for the "trusted" sites that automatically submit entries, I don't see any reason to not automatically approve their entries. However, it would be good to maybe still allow the community to vote them down for revocation, possibly.
If items are submitted in the wrong category, it would work to let uses flag it for moderator review. However, a better idea would maybe let the users click "category flag" and then vote for the new category that it should be. Then if enough users flag it in the same new category the site could automatically change the items category.
Yes, I agree that accountability should be a big thing with the voting system. It wouldn't hurt to show the users that flagged an item to change it to another category, but showing who voted something down may cause flame wars in some cases. One thing that StackOverflow.com does is it grants users more rights to do different things once their total score reaches certain levels. This way new or really casual users can't do to much harm, and the more "trustworthy" users with more points can help moderate the site in a way.