Welcome Kitty, thanks for sharing your memories. The great cartoonist Robert Crumb is the only one I've heard of who collected 78s, but he was mostly into Blues records. Here are a couple of websites you could check out to get you started:
78 rpm Collector's Community:
http://www.78rpmcommunity.com/Site that buys 78s:
http://www.old78s.com/78s_we_buy.phpOr, you could try and contact this person who tried to sell a 78 rpm of Welles's Macbeth online:
http://shaksper.net/archive/2007/249-ma ... h-for-saleGood luck. My thinking is that the value of the Macbeth set might be lower since there has already been a CD issue of it a few years ago, although that is now out of print:
http://www.amazon.com/Macbeth-William-S ... 229&sr=8-2