I'm not saying this is THE answer or anything, but it may be a small step towards getting more contributors and outside participation.
We've been holding hackathons instead of demo camps for the past couple of years and they've been well attended (20-30 people) and at the end of the evening we have had 4-5 patches that are good enough that with a little polish can be contributed to the code base. Granted, we haven't had any long term contributors or committers come out of this, but at least it is introducing newcomers to open source and the Eclipse community. I've generally found the experience more rewarding that the demo camps.
It's still a bunch of work for the project leads: making sure the getting started docs are up to date, and finding/creating a bunch of bugs suitable for newcomers, etc. But this is something that is a lot of work up front and then it pays off over the long run.
This is not a way to get people to fix the hard bugs, and it's not really a way to save work for project members (since any bug that a newcomer can fix in an evening is something that a project member can fix in a couple of hours). What this really does is bring life into the community and make it seem like Eclipse is not "dead". And maybe over time, if enough hackathons are held, this is a way to slowly turn people into committers.