It' standard practice to color code DAPs by different memory sizes (look at the T10 for instance, or even the old IFP models). It makes it easier to recognise when someone has a 'premium' unit in their hand. It also makes it easier for the monkeys in the warehouses to ship the right one.

Whether you think red is a 'premium' colour is up to you. Someone obviously decided it was. If you want to spray paint is something different, I guess you can. Or else you can by an iAudio D2 in black/white and attach the decals of your choice.