One way to help improve Open Source projects is by offering "bounties" to developers providing specific bug fixes, feature enhancements etc. One such platform is Bountysource - other platforms are available. Bountysource charge a fee to maintain the service. Some may view this is an unwarranted free market intrusion into Open Source, others may view this a reasonable fee for a useful "added value" service.
Bountysource integrates with repositories hosted on github, so KiCad source repo is not there, but KiCad libraries are. However, it is is possible to create a dummy repo, which can be used to track and award bounties, even if the KiCad source code is maintained in launchpad.
It might be obvious, but worth saying - any submitters hoping to get a bounty must be prepared to engage with KiCad devs or library maintainers to get a submission to an acceptable standard.
If anyone thinks this is a good idea, it would be easy to set up, but right now I believe that bounties could be placed on KiCad library issues.