A couple of blokes over here have built up a very close replica of a Peugeot 504 ute/pickup which was homologated for GroupB (yes really). Now most events or is it the "higher body" won't let them run as it's based on a commercial vehicle, even though it has been paperworked through FIA.
Seems there is no easy situation for anyone. Right now here in the UK even a very correct Escort is NOT the way to go rallying as the organisers want different cars, so they are accepting others before Escorts. This is vaguely on thread?