Open innovation tends to be heavily focused on the front end of the problem: understanding the opportunities and needs, generating ideas, and starting to prototype to test the ideas. From that point, the work mostly turns back to the individual or team to drive the idea forward, in pretty traditional ways.
I'd love to see OpenIDEO invest in the "building" phase that follows ideation. There are great open source and maker communities all over the world. OpenIDEO could build connections with those communities so that top ideas coming from a challenge are then brought into these "implementation" communities. OpenIDEO could build a platform or (more likely) integrate with the existing platforms used by those communities to support the building process.
This would give the team that started an idea a wide set of expert resources to work with to build the concept to the point where it is a real (albeit nascent) initiative. It would address one of the biggest challenges in any entrepreneurial effort: getting access to the resources you need to make the idea happen.
Open source and maker communities share the same collaborative, open values as the OpenIDEO community. And they tend to be motivated by challenging questions worth solving. So it seems there could be a good match there.