The links below are all the (sold in the US) "sub-mini" tube radios made for consumer use that I am aware of. I have seen promotional advertising for others but to my knowledge none have surfaced (such as one advertised by Sylvania). I would be very interested in learning if they are additional brands and models not listed below. Very little documentation is available on these most interesting sets. The few that were made was at the early stages of  transistor development which took over the portable radio market in the mid 50's. Some of the later submini tube sets omitted the output tube and replaced it with two transistors and referred to these sets as "Transistorized". Some of the earlier submini sets incorporated one or two miniature tubes as well for some reason such as the Motorola & Silvertone.