It is 2 floors, and the basement, to me, looks like it could be another aptm - separate entrance, high ceiling, lots of open space.

Common shared entrances?

It's a huge houseand it has a seperate entrance for the business about 20 feet right of the front entrance to the house.

Both units have separate entrances, laundry hook-ups, separately metered.

There are two separate entrances and fully separate kitchen/living areas (upstairs and downstairs).

You know this area - a nicer separate entrance lower level 1/1 apartment could fetch $1100-1250 or more depending on the area.  

Quick roundup, get ready for this:18 units (going from studios to huge luxury lofts) spread over the upper floors of 3 retail stores (big franchises) in the main shopping street (one entrance, 3 addresses, if you follow). 95% of the construction done...

Put something up at the entrance that discourages vehicle use but can be opened for use by emergency vehicles and for the occasional moving in/out of big items such as furniture.Tell the tenants this change is a result of their not being able to work out a more viable solution between themselves.

I've looked at duplex's across the GTA but also single family dwellings with an "in-law-suite" or separate entrance for the basement apartment

With my sublease deal I should be signing now on my existing unit, and what should be a good AirB&B rental in my new apt in the building, (w/ 2br/2ba, w/ 2 separate entrances), close to BART, 1 block from Lake Merritt, studs-down remodel..