Trusted users (20k+ reputation) can delete downvoted answers and closed questions immediately, only three votes are required. Spam flags take six votes, but can be cast by anyone able to flag (15+ reputation).
For spam answers, this means theoretically trusted users could remove them with three votes, though this doesn't work for spam questions as they would have to be closed first.
I propose that users with the trusted user privilege should get spam flags that count double, so three trusted users flagging as spam would validate the spam flag, or two trusted users and two normal users as well. This would essentially translate the deletion power of trusted users into spam flags, allowing spam to be deleted quicker. I also think that requiring at least three users is enough to prevent misuse of that feature.
One way to prevent abuse of this feature for ambiguous cases would be to restrict it to posts from 1 rep users. Pretty much all blatant spam is from users that never posted anything of value to the site, and never received a single upvote.