The 1970's Frigidaire Skinny-Mini stacked sets as well as the 24" GMini compact washers actually do that! Instead of the Rollermatic transmission and pulsating agitator, they use the Synchro-Swing mechanism with a one-piece molded polypropylene tub and agitator, or Agitub. I'll scan a few pages from the Tech-Talk later, but the mechanism is a very simple, reliable design, IMHO.
I saw my first Agitub run at the Convention, and I was surprised at how wicked-fast it agitated! They're a little faster than a belt-drive Kenmore (which is 68 OPM on high), but with a longer stroke, and of course have awesome turnover. There's a video in the "See It Wash" section of an Agitub rinsing, but that doesn't do it justice as far as turnover is concerned...you really have to play with one in person to enjoy it. Yet another great design that fell victim to WCI, unfortunately. They sure hold a lot more than the Franklin-design compacts that followed...I have never seen such a tiny tub in a machine in my life.
--Austin