Any limit switch that can provide ground to the Talon limit switch input pin will work. So basically any limit switch.
The quadrature pins are 3.3V level, 5V tolerant. So 3.3V and 5V quadrature encoders are both supported.
Encoder breakouts...
http://www.andymark.com/product-p/am-2633.htm
http://www.vexrobotics.com/217-4398.html
3.3V analog sensors are also supported (potentiometer or active sensors like magnetic encoders for example).
If you want to use a 5V analog sensor, you can use the analog encoder breakout which level shifts a 5V signal into a Talon SRX compliant 3.3V.
http://www.vexrobotics.com/217-4401.html
http://www.andymark.com/product-p/am-2634.htm
Please read the Talon SRX User's Guide for more info.
(
http://www.crosstheroadelectronics.c...ol_system.html at bottom)
Every motor gets power from an individual motor controller. However you can programmatically instruct one Talon SRX to follow the throttle of another. See the Talon SRX Software Reference Manual for how to do that using programming API.