Given the popularity that we see for the re-releases.
A proper 'pencil nose' Peterbilt, perhaps in a simplified assembly theme (that could still be bashed with other kits) would be a huge hit, IMO. A B-Mack would also be a winner, again, simplified but bashable.
Not sure of the commercial reception for a 4-door Valiant. but, most of the Duster kit would still apply.
But, that's just me and I could be wrong about that.