I would recommend a lightly-used Kenmore standard tub Ultra-Wash or Whirlpool Powerclean (basically the same machine). They stopped making these about 2 years ago but I have bought 3 of them for friends and family off of Craigs List in the last few months. I have personally owned two of these machines since 1997. The first one is still going strong in my brother's house and the second I have had for 10 years. They are one of the best dishwashers EVER produced in the American market.
I second looking for a lightly-used standard-tub Kenmore Ultra-Wash or Whirlpool Powerclean. The vinyl-covered racks were a weak spot on our first Kenmore, but the one we currently have came with nylon-covered racks, which I'm hoping will last longer.
Would be a great replacement. If you can't find one of those machines look for any standard tub WP/KM machine with the Powerclean/Ultrawash power unit. Another good replacement would be a Maytag Intelliclean standard tub DW. Avoid many modern DW's as they wash anemically for 3 hours with a teaspoon of piss warm water and don't clean anything. These sorry excuses for a DW rinse even worse and leave soapy, gritty film on your dishes. Most of them also shit the bricks after 2 years or less.
WK78