Really depends on what sound you're after. You playing mostly clean or distorted? Do you need more of a "chunk" or more of a jangly single coil sound.
If I had a mustang laying around, I'd stealthily hide an old hotrail pickup under the bridge pickup cover (the older hot rails somehow can fit in Mustang covers, some guy at Shortscale did that a few years ago), wire one pickup switch for pickup selection, and the other for some neato tonal options (series/parallel, phasing, coil tap, and so on).
As for my choice in colors, probably black pearloid with black pickup covers and switches, but that's my preference.
