An interesting question. If you look at the early 1930s and before, none of the manufacturers of what many today call "antique" radio gear were in existence. I think you'll find that almost all commercially made ham gear before that time period consisted of receivers. I suggest you obtain some QST magazines from the 20s and early 30s and read through the ads. Here's a link to a QST from the 1920s on eBay right now and the seller included several photos showing receiver ads:http://cgi.ebay.com/Antique-1922-QST-Magazine-Vacuum-Tube-Radio-Electronics_W0QQitemZ130083728527QQihZ003QQcategoryZ29223QQrdZ1QQcmdZViewItem
I've found that many of the old ads for receivers that cover the shortwave bands didn't refer to amateur radio at all. Another magazine of the period was Radio News and you'll find a ton of them on eBay as well. I have a January 1936 issue here with a column called the "Ham Shack" that introduces the reader to the "new" Hallicrafters Super Skyrider receiver and the National HRO. Other ham receivers shown are by Montgomery-Ward, Browning and RCA.