"In either case, I'd put the appliance on a shelf..."

"There must be a minimum of 12" (30.4 cm) between the equipment and any surrounding walls. The surrounding walls must be made of noncombustible materials. The equipment must be installed in accordance with local fire and building regulations." -- Operators manual

"I typically use my toaster oven for cooking small meals and sides..."

This $1700 appliance seems like incredible overkill for home use.

There are other half size commercial countertop ovens as "low" as $550 - I've never heard of those brands, but could roll the dice.

Either way, the cost would be significant - but it is the only way I can have double ovens. For big dinner parties, I've often wished for a second oven.

The clearance is a good catch - hmm, it would be difficult to find that much clear space.

There's a reason consumer level toaster ovens don't heat as high as commercial. They can be placed with less clearance. I've even done a consumer level Breville on a "microwave shelf" type cabinet, and had it work. If space is a premium, and you really want the commercial one, open up the wall and install steel studs. Then use a commercial 24" deep stainless microwave shelf. And do a stainles type pot rack or shelf above. Something non combustible.