LED Panel Design. Arduino or other.

We are looking to develop a high luminosity through-hole LED panel comprising of a simple fixed text (8 letters).

The panel will be used in an outdoor racing environment. Tests on LED matrix panels have proven unsatisfactory in terms of brightness / visibility in sunlight.

In total there will be 267 LEDs split as follows:
Letter1: 36 LEDs
Letter2: 38 LEDs
Letter3: 38 LEDs
Letter4: 42 LEDs
Letter5: 34 LEDs
Letter6: 22 LEDs
Letter7: 22 LEDs
Letter8: 35 LEDs

We are considering using 30000 mcd LEDs but will be guided by the developer:

1) All LEDs should be turned on or off at the same time (there is no scrolling / flashing requirements etc). Simply on or off.
2) The display should automatically turn off after 30 seconds.
3) The design should minimise the amount of manual soldering required.
4) We require recommendations regarding power sources (e.g. 12v 4ah battery etc)

Price quoted is negotiable based on experience and speed of execution.