through the wall heat pump needed

I am trying to find a two ton through the wall heat pump that can be piped to an air handler. The application is that the job originally had a magic pak packaged unit installed in the exterior wall. 25 years ago that unit was replaced with a Trane air handler, and heat pump. Both units were installed in the equipment room that is located on the balcony of this condo. They put a reverse elbow on the condenser's discharge, and ducted it out through the top of the existing wall sleeve, while leaving the bottom open for intake air. While this has worked fine, I don't think it would be a good setup for the higher efficient( and physically larger) split systems we have now. I would prefer to put the through wall unit back in and pipe it over to a new air handler.The size of the wall sleeve is 24.5" wide x 34" high. any assistance would be much appreciated. Thanks to all.