I'd like to see Atlas do a Wheeling & Lake Erie steel triple hopper by FreightCar America. They would compliment the upcoming W&LE SD40's very well. The MTH version of this is pathetic.
Also, since Atlas makes a Trinity 5161 cu. ft. grain hopper maybe they could do the smaller 3281 cu. ft. version for sand/cement service. I don't think this hopper has been done in O scale yet.