Rack and Pinion Drive with integrated motor and stops

Does anybody sell an inexpensive rack and pinion assembly with integrated motor and stops? If not, is there a motor with end stops that can be easily attached to a dual track rack/pinion? I want to do a motorized art cover for wall mounted tv.

Thanks

Thank you for the recommendations. I sent them an email, but I don't think they have rack and pinion style actuator. This is what I am trying to do on a budget. It is basically a roller shade and a rack pinion actuator. I am trying to avoid buying the roller shade and actuator separate and I am looking for a supplier that offers dual rack and pinion actuator with a built in motor.

http://www.mediadecor.com/eclipse-vertical.html

No luck with them. They don't sell rack/pinion style mechanisms. At this point I'll be happy with a rack and pinion assembly that has the roller guides integrated. This is the only thing that I found, but I want to be able to attach a motorized window roller shade as the drive and it does not appear to be possible with it:

http://www.e-motionllc.com/RACK_AND_PINION_LINEAR_ELECTRIC_ACTUATORS_s/1.htm