OK, I'll test my mac ingest again, but I clearly remember having to rename the avchd related files back to their original names so that I could get them into iMovie as a camera archive import.
I guess this potentially begs a slightly different angle, that of ingesting avchd files from camera cards - could they be renamed by photomechanic upon ingest as other movie formats can? I'm not aware of DSLRs using avchd format, but panasonic 4/3rds cameras certainly do.