Timed Infrared or Infrared PWM Signals
It is customary to ask one question per question, but as your questions are related to the overall design I'll try to answer them more or less in combination.

What you want is certainly possible, but don't expect any off-the-shelf LED assembly to fit your project: you'll have build it yourself, including the system (probably a microcontroller) that drives the LEDs.

7 meter distance is possible with normal IR LED and normal TV-remote style IR receiver modules (google for instance TSOP IR receiver), but it probably requires a good driver circuit for the IR LED.

Assuming a 7 meter window and 20m/s means that you have ~ 350 ms within the window. That is enough to transfer a few bytes of data (an RC5 message is ~ 25 ms), but reliability will be far from 100%.

You will have to consider spillover from nearby windows, much like cellphones have to do. This will eat up some of your bandwidth: the signals from IR LEDs that are next to each other must not overlap, and there must still be enough silent time to satisfy the IR receiver's requirements.

Another approach would be to use IrDA-style send/receivers, which would enable a much higher bandwidth/resolaution, but I doubt 7 meter would be achievable.