RGB SMD led 5050 project

I am working on an RGB led project for 5050 led strip lights. I just need help/advice with which arduino hardware will work for my application.

I need the arduino to be powered by 12v and be able to drive 1000 or so LED's. I can do this with inline amps if needed. I would like to control the arduino with the 433 mhz Receiver decoder module/remote.

The other thing I need to be able to do is to use a second 12v power source as a switch/input. I dont need to use the second 12v for anything other than a switch such as if input (12v) is on then override what ever programming is happening at the time and do X. Then when the 12v input is off go back to the original programming.

I just need the smallest hardware possible that will accept the RF remote control module and allow for this second 12v input to be used as a switch.

Any input/guidance will be greatly appreciated.

Promini.
Control MOSFETs, Relays, whatever to enable current flow for 1000 LEDs.

Resistor divider to knock 12V down to 5V as a digital input.