We stumbled across an even more amazing find after moving in. I cracked open my first issue of Smithsonian magazine and saw a little blurb about the first microwave ovens. Timothy commented that the picture looked like our unidentified wall oven...and a little digging by Chris proved that we were indeed the proud owners of an original microwave.
Speed-O-Light cooking is what it was called in the small informational booklet found in the oven's built-in recipe drawer. It goes on to explain that it doesn't cook with heat, it cooks with microwaves. This microwave had the option of simultaneously utilizing a broiler for crispness, a feature sorely lacking in our modern counterparts. The broiler is still functional, but the microwave--it appears--is not. Still a fabulous find!