Arduino Lightbar

I want to produce a bar which will be - say 50 - leds, to be run by arduino. The lights will basically go from one end to the other, in sequence, then return, then go back, and so on.

Separate to the bar, operated by bluetooth from a mobile, the following:

Start
Stop
Count of repeats, zeroised at start
Colours of leds

Red, Yellow, Blue, Green Violet

Intensity (strength) of coulour

Increase speed
Decrease speed

Wiring diagram

Also the option, (please price separately) for the item to have an audio output (to earphones) beeping at each end