I had an Atari PC3. Came with twin 5 1/4's, swapped one out for a DD 3.5". Also added a 40Mb hard card (split into 2 partitions, because DOS 3.2 could only use 32Mb max) Possibly the most pimped-out XT ever ;-) There were dip switches on the back where you could select which graphics it had on bootup (MDA/Hercules/CGA/EGA) , there was also a tool to let you choose which one you wanted at any time. The notable part was not the ST mouse, nor the fact there was a socket for ST drives, but mine really did come with an AT layout keyboard, one of very few (possibly only) XT-class machines to do so. Cheers, Raki.