I think this changes the problem significantly. A feature request is essentially asking people to put in effort for you; that shouldn't happen if you have other options. If you're in a position to build something yourself, or to pay someone to deliver a feature you need, then that should be your first choice. Alternatively, you could propose sponsoring the feature eg paying the project owners to build it.
If the project owners are open to a merging the feature in to the project once it's complete that's great, everyone benefits from your effort/money, but requesting a feature that you could build yourself feels a bit wrong to me.