It is interesting to note that none of the three you contacted specialize in manufactured housing. Check in your yellow pages for dealers that sell Intertherm or Miller, the parent company being Nordyne, or for Evcon or Coleman, the parent company being Coleman. Both of these built units made specifically for manufactured housing. Heat pump vs Air conditioner= The air conditioning side of a heat pump is not as efficient as air only. Air only does not give you the heat savings of a heat pump. The trade off is your choice. In the colder climates where heat is the big concern, the heat pump is more popular. In the Florida area, the split system air conditioner is the preferred choice.
Roy T. Bonney