1. Has anyone had the problem with the blade when inverted the main rotor hits the tail-boom and drops out of the sky?
Wow... I'd wouldn't imagine that's possible under ordinary conditions unless perhaps your rotor speed is wwwwaaaaaay too low. The centrifugal forces shouldn't allow it to get quite close enough to the boom to hit it mid-flight, or maybe your tailboom is loose.. but if that were the case, you probably wouldn't be flying long enough to get inverted anyway.
2. Are there any brushless motor set-ups available for the cp-blade?
No off-the-shelf kits yet. To go brushless on the BCP, you end up doing a complete separates upgrade. New Tx/Rx/ESC/BEC/Gyro/etc.
My blade has a 1320 mah li-po with the 9 tooth motor and carbon-blades. It goes where I ask it too, just seems a little weak for inverted manuevers.
There was a post about advancing motor timing by twisting the back of the can by 30° (1 hour) clockwise -- consider that. And also, do the sticky collective fixes (blade grip washers & centerhub/flybar problems). Maybe that'll help out.