Hey, what a coincidence! The XT I was talking about was the Commodore PC20-III. Same as the PC10, but with a 20Mb harddisk! (not too shabby eh! )
This little box provided me with hours of pleasure, but it annoyed me sometimes too. One of my biggest culprits with it was that it could not read HD floppydisks when most of my friends started using those. (still using 720kb ? Man, this HD floppydisk with it's 1.44Mb gives me OCEANS of space! )
It's still on a box in the attic gathering dust...