Winegard
Winegard makes many portable RV satellite units that can be utilized either directly through a serial port to pass commands to it's firmware, or it's control PCB can be removed and replaced with an Arduino, H-bridge combo DIY custom control system.
Their main competitor seems to be Tailgater. (which may be owned by King Controls? their products are too similar to be coincidence)
Known units
Winegard Carryout* / Winegard Carryout G2* / Winegard Carryout G3 / Winegard Carryout G4 / Winegard Pathway / Winegard Pathway X2 / Winegard Trav'ler* / Winegard Trav'ler Pro / Winegard Playmaker / Winegard Playmaker Dual /
DIY serial cable necessary for some units
Obscure units that may offer some potential?
Winegard Rayzar Z1/Rz6000 (if you have experience with this unit, contact me @ *aesop* [a t] warp-pipe.net)