I have your same problem but have no option to enlarge the vent duct due to the size of the space between the wall and ceiling studs. My previous vent hood was a 36" Cavaliere 900 cfm for a 36" Dacor Epicure cooktop. My new range is 36" DCS with 6 burners. Because I wanted a more substantial look, and after much searching and debating, I bought an AirPro 860 cfm (link below) The Cavaliere hood was more than what I needed for the 36" Dacor. I never turned it up past 1 or 2 while cooking. On 6, the highest speed, it was kinda loud but since I never used it on high it wasn't a problem. The AirPro has not been installed yet so I don't know what the actual noise level will be but it's rated at 35 / 0.7 to 67 / 6.5 (Lowest to Highest Speed). I just couldn't see paying thousands of dollars for a vent hood especially since my $400 Cavaliere had worked fine for 5 years. During my hood research one of the retailers did tell me there was a vent outlet adapter available online but because our contractor wasn't thrilled with that idea, I stayed with the 6" hood duct. Hope this helps. Good luck in your search for the right hood. Here is a link that might be useful: AirPro Hood

Do you have a budget? I ask because there are a lot of things out there but they vary in price. For a range like the NXR you want at least 600 CFM. You also want to look at how you clean the hood. I shied away from the vent-a-hood because some reviews indicated they were difficult to clean.

I don't have the window, but this is what mine looks like. Instead of an island, which would be hard to navigate around if there is more than one person, I used a mobile cart. It's worked out well so far.

The OP wrote: "- We can have a 10" duct, but can not install external blower because there will be at least 3 ninety degree turns for the duct to go through the roof (kitchen is on the 2nd floor and there is another floor sitting above the kitchen)." I must have missed this thread. Just what effect is being assumed here such that the location of the blower is affected by the three 90-degree bends, so long as none are right at the blower. (Hint: Pressure loss capabilities of kitchen hood system blowers are minute factions of an atmosphere. Due to this, pressure losses on the blower intake side and pressure losses on the blower output side have the same effect, particularly when a 10-inch duct is to be used for a sub 1000 CFM requirement.) If one wants [relative] quiet in an open area. the blower should be remote from the hood and a silencer placed in the intermediate ducting. As widely noted here over the past decade or so, rated CFM and actual CFM differ by a significant factor, and one cannot address kitchen ventilation with only hood system parameters. The make-up air system parameters are equally important.