There was a pretty nice project a few years ago, awarding Bitcoin to Tor node operators called Oniontip [1]. All Tor operators had to do was to add a Bitcoin address to their Tor contact info. Donors would transfer Bitcoin to a Oniontip-operated Bitcoin address and Oniontip would regularly pay out the Tor operators proportional to the bandwidth they provided to Tor.

That did work remarkably well, but unfortunately the author lost interest at some point and took the whole project down.

[1]: https://github.com/DonnchaC/oniontip