IMO you need some kind of eshaust system over every range unless all you do is steam veggies.

You need a hood to remove food smells and combustion products from your stovetop -- that means it needs to be right over the stove top. Each stove top. Sorry.

It's called a range hood.

You need a hood, especially if your ranges are going to be gas, they throw way too much heat. Your cabinet finish could fail or soak up steam and warp.

But you cannot put cabinets over a range with a downdraft system, regardless. At least no closer than 30-36" above them. Which renders them useless for most storage.

International Residential Code (International Fuel Gas Code)

G2447.5 (623.7) Vertical clearance above cooking top.

Household cooking appliances shall have a vertical clearance above the cooking top of not less than 30 inches (760 mm) to combustible material and metal cabinets. A minimum clearance of 24 inches (610 mm) is permitted where one of the following is installed:

1. The underside of the combustible material or metal cabinet above the cooking top is protected with not less than 1/4 inch (6 mm) thick insulating millboard covered with sheet metal not less than 0.0122 inch (0.3 mm) thick.

2. A metal ventilating hood constructed of sheet metal not less than 0.0122 inch (0.3 mm) thick is installed above the cooking top with a clearance of not less than 1/4 inch (6 mm) between the hood and the underside of the combustible material or metal cabinet. The hood shall have a width not less than the width of the appliance and shall be centered over the appliance.

3. A listed cooking appliance or microwave oven is installed over a listed cooking appliance and in compliance with the terms of the manufacturer’s installation instructions for the upper appliance.

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http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_24_sec043.htm