Rik with a cutting area that size you are looking at a Bridgeport and that is not a desktop.

For a toolchanger R8 is a no no unless you use the TTS system, i think DENFORD made some mills with a toolchanger but you need to make sure the holders are still available. The holders have to be one taper with a pull stud to hold them in place.

Lathes don't have toolchangers per sa they use a carousel, for the lenghts you will be turning you will need a tailstock with a revolving centre and it is debateable whether the carrosel would be able to rotate while the tailstock is in place.

I thought of making one for my lathe but you can only have up to six stations if your lucky more with a bigger lathe and i use over 30 tools so it wasn't worth it.

Phil