Thought I'd chime in. A second A/C is always nice for those who have the money. It really helps relieve the load of the main A/C - extending its life, as well as increasing its energy efficiency. The second A/C, located over the bed, is not ducted because it runs very efficiently straight down into the bedroom/bath area, basically cooling the entire upper deck of the fifth wheel. Yes, a heat-pump or even a heat strip is nice for the bedroom A/C, especially to provide just enough extra heat as to not require the furnace to kick in. Don't take this wrong, for all of you who are happy with your one A/C, there are just still a lot of people who really want it cold in their RVs and in these big, three and four slideout fifth wheel floorplans, one is not always enough, especially down South.
ST