I don't know of anyone who has actually done it but I think it is a great idea. It seems that once folks start getting royalties they drop off the face of the earth.
The point is for unit owners is to compare statements. The companies know people are private when it comes to money. I have heard of peoples statements having different production numbers from the same well. Having a group like this you can at least make sure everyone is being paid at the same rate. I know people have different deals and percentage rates but the production information should be the same I would think.