You will just have to use the Biblical method:
Seek and ye shall find.
Yes, the in-door silver basket usually served as a coarse food strainer, but it was a very good dishwasher. We have noticed that most portable dishwashers we have found had little use. It seems like people got to where they could afford a DW and then not too long afterwards, could afford to move to a nicer home that had a builtin so the portable went into the basement to sit until an estate liquidation or a clean up when it was donated to a thrift store. Funny how the really choice things have to wait 20 or more years to show up. Often wedding or house warming gifts are packed away and forgotten only to be unearthed and offered up when a retirement or death comes along and they downsize. This was very true with Sunbeam Coffeemasters. In the late 60s, you could not find one in any kind of resale situation, but then, as the population aged some more and, face it the Coffeemaster was not something most young people could afford, the couples that had them started getting rid of them.