The answer is yes, and it does not take more than basic carpentry skills to accomplish. But be aware of a couple of things. First, the kind of hoods you are talking about often have internally mounted lighting fixtures which use halogen or incandescent/CFL bulbs. These produce a lot of heat. To dissipate the heat, there should be be a small louver/vent on the top side of the hood above each fixture. I have seen a several less-expensive of hoods without this venting. the idea apparently being that the metal is thin enough and the internal space large enough to provide sufficient dissipation of the heat from the bulbs. If you get one of the hoods with the topside venting/louvers, you want to design your cladding with cutouts and some kind of grill. (Heavy screening material would work but might look funky. Maybe you could find some brass grill at a fireplace or hardware store. You want to be sure any topside louvers/vents are not blocked with the insulation or the wood claddding. Avoid buying any of the really thin (5 or 6 inches high) hoods that have internal lights without topside venting UNLESS the hood is designed with LED lighting rather than halogen or incandescent/CFL. (LEDs produce much less heat.) Second, many "hoods" of the kind considering are designed with flat bottoms -- which is to say that they are venting devices but not actually hoods. That does not keep them from working pretty well, but it does mean that you will have exposed wood cladding right at the edges. Or, if you decide to mount the hood a little high, you could have the cladding extend down to give an actual hood. Either way, you need to be sure to seal the edges of wood cladding. Do not depend on a coat or two of inexpensive paint or varnish. Get (or have your contractor use) sealers or paint that can take some heat and the moisture/steam-condensate.

Well some kitchens are designed with the upper cabinet opening 6" wider than the range to accommodate. The 24" depth is what I would think is unusual for a non pro range or cooktop. Your head would be underneath a 24" or deeper range hood. The canopy of the range hood is not coincident with the workings of the range hood. My cheapo range hood, which will be replaced when the kitchen is renovated has a motor and screen that is about 12" wide and deep in a 36" wide range hood. And that is probably what is in the 24" wide and 30" wide hoods. The inserts are smaller because they are just the guts and are meant to be put into s larger canopy, because a certain amount of that big hood is not motor or fan it's empty real estate.

We did an insert with a custom hood cover that was built around it. If you did a regular under cabinet vent wont the controls be in the front and be covered up? Like the one you posted? My controls are up under in the insert . The front panel of my cover can be taken off if we ever have to work on it or unplug it. I guess you could make something custom for an under cabinet vent as long as you can access the controls.

”Ductless” is a misnomer. Recirculating is the correct term. That means you have to provide a route in and out both for the air to be able to come out somewhere. You need a custom stainless insert for the bottom, to cover any of the exposed wood, or you’re creating a fire hazard. Plus you need a big ugly opening grate for the air to recirculate. Or to duct it into an adjacent room, etc etc. Lots go into this, to make it safe and effective. Otherwise it’s a grease catcher that has a high risk of catching on fire.