tire presure would be insane... my caddy has transmitters in the wheels that transmit there own unique identifier code along with a preasure reading whenever they spin & transmit all throughout the driving time & stay on for a while after you stop, you can see the actual preasure, that would be really cool,I would definatley want to do this in my montana if this is possible, I think all 4 transmitters cost me around $175 though wholesale, & I don't know what would be needed as a reciever or software wise, but this would be a hit for sure, considering the pro rv systems are over $300
servo's, although you did say that's later, would be awsome too.
as far as accessories, one that comes to mind is a current flow reading device, IE a shunt... you could use 25 amp & 50 amp modules, these could go in line with the desired device that you want to monitor
just a thought...
Different sets of HVAC controllers... for the 3 major types of HVACs I'm always reading about on here... fully electrical, pressurised/mechanical, and the ones in between.
That is if memory serves me correctly
We can sell things like relays and temperature sensors, but it will be up to the individual person to fit them to his/her car