I went to the EAA class on "buying a used experimental" where alot of this stuff was discussed.
The idea is that since experimentals are becoming so common, that these issues of reselling need to be brought out for discussion. Basicaly I came away understanding: The plane must be amature built 51%. No one cares who those amature(s) are (were) as long as they were non-compensated (and you can prove it). You must convice the DAR of this. A builder's log is one good way to do that. Anyone, but only one, can ever sucessfully apply for the repairman's certificate for this aircraft. Usually this is the person most involved in the construction, but it does not have to be. You can buy a plane that is complete and built by people or persons within the 51% rule, a plane that you had nothing to do with the build, and still you can get the repairman's certificate as long as no one else has applied for it. A DAR will not like to give the cert to someone with no repairman skills, and may balk at giving it to you if you did nothing whatever in the build, another DAR may approve it because doing so fits the rules. (feel free to chime in here if you have the exact reg on this) I bought a complete experimental, the guy with the repairman's cert for the plane died of natural causes. No one will ever again have a repairman's cert for this plane, and it was priced to reflect that when I bought it. It will always have A&P inspections, which I think is a good thing anyway. jg