I posted last week about my 06 R6. I changed the oil and filled it back to the middle of the hatch marks and the oil level light stayed on. Some of you said that you had seen similar problems where you had to fill the oil to the top of the hatch marks to make the light go out, etc.
I filled my engine to a little over the hatch marks (but didn't start it) and the light still stayed on!
I considered taking it to the local stealership, but they wouldn't take me in until a week from now. What's up with that!? Nevermind that. I'll do this myself.
I first tried just tapping on the bottom of the sensor area of the case with my rubber mallet, thinking that the level float was stuck. Nothing changed.
I drained the oil, leaving the filter in, and pulled the oil level sensor out, without disconnecting the cable from the harness (connector is tucked away somewhere anyway). The level sensor has an externally caged ring-float which rides up and down on a short post. I think the technology is such that there is a sensor element in the post which can sense the location of the magnetic float.
One of the bolt holes for the sensor has a metal terminal which must be grounded. The bolt makes ground connection with the engine when it's bolted in place. With the sensor just dangling there, ungrounded, the oil level light will flash. When I jumpered a ground connection from the sensor-bolt-hole-terminal to the engine, then the light would go on or off according to the float position.
Next, I checked the operation of the sensor. The float seemed to move up and down freely without any hinderances. I noted that the oil level light would come on when the float was about 1/4 distance from the bottom. Any higher than that and the light would go off. There was about a 1 second delay of the light reporting the current level condition. This was very repeatable.
Obivously, the key was on during all of this.
I put the sensor back in and started filling the oil. I found that the light went out after putting 1.75 quarts in. I also found that oil just started showing on the botton edge of the dip stick hatch marks with 2.1 quarts. The oil level was at the middle of the hatch marks at ~2.75 quarts.
So everything is cool now with the sensor.

I am suspecting that the float thingy somehow got stuck to the bottom of the sensor and would not float up correctly. Either that or it got in a bind on the way up. Either way, it's somewhat dissapointing.
Anyone who says that their oil level must be somewhere higher than the lowest hatch mark, in order for the light to stay off, might be having similar sticking problems with their level sensor.