We're considering updatin some of the appliances in our kitchen but do not want to remodel the original kitchen. Our stove and oven jet out of a wall that separates the dining room from the kitchen. It's like an island that is connected by one shorter side with no direct connection to the outside. Is there any possibility of venting above the cooktop area without some huge ghastly appliance sitting two feet above? That would look pretty silly with the lowered cooktop area, and that little fan sure doesn't do the trick. Is there such a thing as a ventless vent? There's an amazing Gaggenau downdraft system that pops up from the cooktop area (so an above island venthood would not be necessary), but it still looks like it has to vent out somehow. Any suggestions, please??
I had the same situation in my Eichler. I used a down-draft fan and ran the output sideways over to a post. It didn't attract any attention going through the roof next to the post. The duct I used was the same thickness as the post and looked like a painted beam. You should talk to some of the remodelers on this site. They solve this problem all the time and would love to give you some ideas.
Actually there are a number of ductless range/cooktop vent fan appliances available. They use several filters and work fine; the issue is that you need to replace the filter every year or so, depending on use. That might be the best solution for your quandry.
I can suggest trying kitchen appliance suppliers in your area.