Hi Mike,
James Chapman of Sheffield were making braces, in sweeps of 5, 7, 8, 9, 10, 12, and 14 inches. After their take over by Stanley in the mid 1930's the range was reduced but the 5 and 6 In continued for a while. I have a 6 In Stanley branded No 73E MK 4 with the plastic handles that Richard mentions and it is very handy for driving screws. As well as the slotted driver bit I've also got a Phillips bit that fits the brace.
Here in Aus' the smaller sweeps used to show up at swap meets etc quite frequently but haven't seen them so much lately.
Cheers,
Geoff.