Roy Smeck played Hawaiian guitar in Vaudeville for most of twenties and had recorded extensively before 1930 and by then was quite famous. Alvino Rey started playing with Horace Heidt in 1932, and was also very well known, owing to Heidt's radio program. The first commercial guitars and amps were introduced around 1932 by Rickenbacker, but Bob Dunn, who recorded around 1935 with Milton Brown and his Musical Brownies, made his own instrument and amp. He also created his own style of playing, that had much more to do with jazz soloing than anything else.

Thanks for reminding me of Milton Brown, Frank--he, and his band, aren't much remembered, and they are worth listening to, and important--if for no other reason than they show that Western Swing and all the "country" music that came with and after it are really cleaned up, commercialized jazz and blues.