IMO, there is no user need for this. As a freelancer, putting my client's work in someone else's hands would be more stressful than me doing the work on holiday

IMO, there is no user need for this. As a freelancer, putting my client's work in someone else's hands would be more stressful than me doing the work on holiday myself. If you're problem is that you're weak at finding work, would it not be easier to hire someone that would specialise in that & put them on a commission basis?