I'm not that familiar with the g force (yet haha, i need the money first) but I'm sure I read somewhere it has a 2 voice harmoniser. Plus user custom scales. Is that not what you mean by dual intelligent harmonies?
I don't know the intervals from Ballerina 12/24, but presumably you select the pitch function, choose intelligent harmony and your scale and then set the interval for each voice. Only problem would be if Ballerina goes above an octave, the g force has a max of one octave up or down I think.
Hope that helps in some way.