Just curious... Was it Athearn or Walthers that produced the trinity PD hopper? This was the kind that Wonderbread used. I'm an N scaler and the recent Athearn anouncments in N scale (the food lading boxcars and the gsc 53' flatcar) leads me to belive they are reproducing past walthers products. If Athearn did Produce a PD hopper in HO and they did the R&D for the walthers N scale, then they might redo the N scale PD hopper as well.
The Trinity Pressure-Differential hoppers were done by Walthers. FWIW, the fact that a few of the new Athearn N-scale releases mirror a couple of past Walthers releases is coincidence, nothing more.
There were also Airslides done in Wonderbread in HO by Walthers. Dunno if they did them in N scale though.