You can probably find colleagues easily. The challenge is interesting them in a collaboration with you.
The basic rule is that collaborations are successful when everyone benefits. In order to get collaborators, you need to make it clear that they will benefit by working with you on your idea. Benefit in academia usually takes the form of:
- Funding
- Publication authorship
- Advancing the collaborator's pre-existing research interest
You have already mentioned one potential benefit of your work: high-impact publications. The key is communicating (and convincing) colleagues that they will benefit.
Here are some things that might help:
- Have a concrete proposal. While some open-ended early discussions might be useful, once you are ready to invite people to collaborate, invite them to something specific. Do you want to write a paper together that demonstrates XYZ? is a clear idea that colleagues can quickly evaluate to decide whether they are interested. On the other hand, Should we work together in area X? is way tofar too open-ended. It is not clear whether it will lead to anything useful, and busy academics will be reluctant to invest a lot of time in discussions that might not lead anywhere.*
- Demonstrate credibility. A colleague might be interested in your idea, but still reluctant to get involved if they don't know whether you are able to accomplish what you propose. The bigger and bolder your idea, the more skepticism you are likely to face from others. Some ways to demonstrate credibility:
- Existing track record (publications, etc.)
- An introduction from someone known who can vouch for you.
- Networking and conversations that give people an insight into your knowledge.
- Offer to collaborate with others on their ideas. You ought to be the kind of colleague that you hope others will be for you. This means being willing to contribute to other projects. Offering to help others, besides being nice, also gives you a network and credibility for advancing your own ideas later. And in practice, advancing your own ideas often means compromising with someone else on a project that does some of what you both want.
*When I was trying to get collaborators on a grant application, I made the mistake of being too open-ended. It seemed like appropriate deference to others who were more experienced to approach them without a well-formed idea. However, these discussions didn't go anywhere. Eventually I realized that making a clear, concrete proposal was a service to everyone, as it gave them a much better idea of what I was talking about and whether it was worthwhile. "Let's apply for funding from this specific grant call, based on this short summary idea" got an immediate response from others. In the end, more experienced colleagues did shape the proposal quite a lot, but the specific proposal was a much better starting point for successful collaboration.