We lived in Prescott Valley for five years before we moved here & built a house. I thought the climate would be similar, but a couple differences have become apparent. First off, we're in zone 6, but a bigger thing is that we live at 7100 ft elevation, and get quite a bit of snow. Not Flagstaff snow, but more than I was expecting.
I see your point about the heat tolerance--although several have said their Chanteclers do fine so long as they get the same kind of heat-care other heavy breeds do. The main thing that may shy me off them is a low fertility rate. Not because they need their fluff trimmed, just a low fertility--even Cackle rates them at around 50%. I may still try a few, just to see how it goes.
Most likely I'll end up just going with common dual-purpose breeds, and then maybe later, once I have more experience, I'll get adventurous.
Sorry you lost your rose bush--I hate when that happens!