Hi bikesnbones,
From my experience, check 2 things.
1st) check for dampness where motor and trans meet. While my ride didn't use as much as yours is, it did have a small rear main leak at one point.
2nd) And most likely, "To what point on the sight glass do you fill the oil?" And, "Do you park it on the side stand?"
On my bike, if I fill to the point where the oil is above the dot and parked her on the side stand, she would smoke lightly and make oil disappear until it was half way between the dot and the bottom of the circle.
I could keep topping off but as long as I parked her on the side stand, that top off would disappear.
Also, not to start an oil thread but my girl likes the 20w-50. 15w-50 mobil synthetic is what she liked to make vanish. This doesn't worry me to much. She's gonna be at 80k miles by the next oil change. So long as compression is good, she doesn't leave an oil trail or cloud and she runs smooth....I'll ride her.
Hope this helps,
Freelancer