Small would be something around 3000lbs and 5hp. I can deal with a bit bigger weight wise - say 6000 lbs and more power, maybe 15hp max but it has to be a bit "compact". i.e. I don't want it to take whole garage.
Partner 1 comes in at 4500lbs and 7.5hp - plus its not overly big also seems to not fetch a huge price - if you can find it (based on US market). I.e. if I were to go and ship from US the price seems to be at around 5000 CAD for supposedly working machine.
A lot of more modern machines are simply too big - we are talking about like 25hp and weight class of 12000 lbs. Not to mention large space needs.
Hass mini mill would be a perfect machine. I would even go Tormach for the right price (through this is unlikely for some reason people like 1ph and want to pay more for it).