These brushless motors have a decent performance but no built-in encoder http://www.ebay.com/itm/QTY-1-Nidec-Miniature-Brushless-Motor-DC12V-PWM-Speed-Control-/221950433234?hash=item33ad46d7d2:g:HKcAAOSwys5WVRUp
The encoder the manufacturer can provide is just 100 CPR so that is not good if need better resolution than that.
You can get the CAD from the public model https://cad.onshape.com/documents/0acf1827233346b9ba139ed7/w/f650e400c4494ff2be283905
| Magnetic_encoder_-_magnet-holder4mm.stl | 562.6KB | |
| Magnetic_encoder_-_Nidec.stl | 1.1MB |
