You are likely thinking of the Xerox Star aka the Dandelion which was a product of Xerox Business Systems (a spinoff from the PARC work). I didn't look too closely but if one of the packs has XDE on it (the Xerox Development Environment) then you'll get the same windows experience that was demonstrated to Steve Jobs back in the day. I'm pretty sure you could run XDE on the Alto (my wife worked at XBS while I was at Sun and there was a lot of cross mingling of technical people at various social events but my memories of exactly what the Alto was capable of are more limited.) We had a get together once over at the office and booted mazewar on six or seven Altos and that was a lot of fun.