I  think there's really quite a bit of info on the web about the BN-1. i do plan to thoroughly scan and document the thing before ( "IF") I assemble it. 

There was a QST article about a single dual section tube, ham transceiver. I have it somewhere but don't remember the date, but prewar. It used a more powerful tube than the little 3A5 of the BN-1. The BN-1 like the AN/CRC-7 however could alternately heat sections of the 3A5 filament to simplify T-R switching.

There was a commercial ham radio retro product of maybe a decade ago called something like "the One-der" which was basically the BN-1 circuit in a modern package. Its price was no bargain and i declined. I also thought the "retro" aspect was just dumb.

As i understand it, when the final  Midwest Radio auction was held, Boy Scout groups bought a lot of remaining radios for group projects. This as you can well imagine seems to have pretty thoroughly thinned out the remaining stock.

-Hue Miller