Corner Robes can be created in all shapes and sizes the larger the corner the greater the access.
The minimum rear dimension would be 5 feet x 5 feet which is a front dimension of 3′ x 3′ . if we have to go smaller than this we can use hinged or bi-folding doors. We nearly always use a curved hanging bar in the corner and work from here with either shelving to one side and maybe long hanging to the other.