In general, I'm a big believer in putting one's money where one's mouth is. I have done several "unconventional" deals in an effort to be fairly compensated. Some have worked out great, some not so well.
Being willing to do a deal like this is also a good way to call a client's bluff on not being able to pay you, BUT you should only do business with people whose interests are aligned with your own.
When far apart on contract terms with a potential client, I've sometimes suggested a bonus based on achieving their goals. I've done remarkably well on those. Actually taking an ownership stake in a project is by far the most risky option, and has not worked out well for me previously. For one thing, you're most likely to be offered this if the project is iffy to begin with . . . Mike Keiser did not offer it for Pacific Dunes, sadly. I know several architects who have taken an "equity stake" in a project, only to find they have no way to cash out when their partners start running the place into the ground. And even if the project is successful, you're a minority owner, so you really have no control over how the place is operated or how and when profits are paid out.
[And yet, I've taken an ownership stake in our new project in Ireland . . . go figure!]
For CommonGround, which is owned by a nonprofit, I deferred my entire fee to be paid long-term as royalties, which are tied to the green fee and the number of rounds played. I would do that again in a heartbeat for a similar public course project. I feel like a true partner in their mission, and the royalty is like a pension for me; they will be paying me [or my family] until I'm eighty.