I just got these fresh of of ebay and it was love at first sight, i have a feeling they are from the thirties but no solid backing, the brown pair is like a suede and the black have a thick leather heel...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=8137547132&ssPageName=STRK:MEAFB:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=8138684805&ssPageName=STRK:MEAFB:IT
~anne
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=8137547132&ssPageName=STRK:MEAFB:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=8138684805&ssPageName=STRK:MEAFB:IT
~anne