@tokyoracer,
I feel you pain. It was much easier to search by "category:vintage computers" to capture pretty much all the Amiga, Atari, Commodore, etc., you know what I mean.
After the ebay change I found that I was missing auctions due to the lack of my search scope, so I had to be more inquisitive with my searches. I have set up an advanced search that includes those systems I follow auctions on.
Just go to advanced search up top and detail your search, then save it. It has worked for me. Hang in there........ ;-)