I knocked up a script (http://modern.dj/app/#ajaxPlease) for my padkontrol and it works better than the APC40 in some respects. A few problem being that it has (obviously) fewer pads, no visual feedback, and a whole row of pads is knocked out for navigation.
The main benefit is that IMO it FEELS better to trigger with and i can just jump into drum racks by changing scene, complete with the aforementioned velocity, and drumrack pad navigation from the mouse.
Anyway, I just think one of these music tech companies should have made one. Like, yesterday.