yes, but are they erected to code? We need to have ~13' of exposed pipe. I don't see the issue either, as long as it's properly braced. Putting a hole in the ceiling where we'd like it also baffles me, as I don't see the problem. I need to ask our builder why he's not liking that location.
You need to have (10X12)+24" = 144" (12') of exposed chimney on a 12/12 pitch. Maybe your installer doesn't have scaffolding or a Manlift to get up that high? Is there another reason why he feels that he's unable to do it safely?