Earlier today on IRC we were discussing the idea of a system which would extract patches from newly submitted Problem Reports in FreeBSD's ports, and (attempt to) apply them to a checkout of the port against which they were made and then if the application works run a tinderbox build of the port to see if it compiles cleanly. The script would then followup on the problem report with the status and tinderbox logs (if appropiate).
As linimon@ pointed out we already have a number of the necessary components of this chain of events implemeneted. The new web gnats PR reader has very good patch extraction capabilities, and automating applying a patch and running a tinderbox build is reasonably easy (with some deference given to figuring out the appropriate level with which to apply the patch), and a way to post follow-ups to PRs.
A tool like this would probably be very useful since a lot of times I think that as ports committers we can be scared off by certain types of PRs which may very well be well written. Java PRs especially come to mind, as they often scare me off. I think it would without a doubt speed up the PR turn-over rate, and would also probably get a lot of ''scary'' PRs committed and closed faster.
As far as implementation, it doesn't seem incredibly hard, extract the latest patch (though this becomes harder when we get into issues of whether patches should be applied over or instead of previous patches), apply it (again a couple of issues can crop up here), tinderbox it (this part is probably the easiest), follow up with appropriate information (also fairly easy). Many of the tools that would be used in this setup (like the patch extractor) are written in Perl though, so I run away screaming at implementing this (that and ENOTIME), but I think it would be a worthwhile project to see done. If SoC applications weren't already over I'd suggest it as a potential SoC project since it's fairly confined.
Anyway, if someone is interested in doing this I'd be happy to discuss it, and help out where time and knowledge permit.