Daniel,
I know you were looking for more, but here are the pieces for the interior set. I have also included for reference my in process scratch build parlor front interior for a conversion of the Model Power open end platform coach to a PRR Queen Mary / Wabash RR Parlor Observation. The MTL parlor doesn't quite fit the MP car.
Bobster
Guess you gotta be logged in to see them, sorry 'bout that