I've been lurking around poaching ideas off this site for awhile now and it's time that I give back a little.
This is my DIY hood/heat shield that I built of of slotted steel, galvanized sheet metal and a heat duct ceiling box. I got all but the ceiling box, duct work and blower from Home Depot. The blower is Broan 1,500 cfm external blower that I found on-line on sale for ~ $600, which was marked down from ~$1200. It's connected through a 10 inch duct. It uses a 6 amp variable fan speed controller. The cost of the materials was a fraction of what a 6 foot ss commercial hood would have cost and by DIY, i was able conform it to the available space easily (no rough-in kits tequired).
The only problem was that once I got rolling, I couldn't stop without putting down a new epoxy floor over the decades old concrete. I got their Ultra floor kit, which is pretty bomber. I etched it once and then used an angle grinder on the tough spots.