There's a guy I know in Sydney who sprayed the entire case in vibrant yellow. As far as I remember, he masked around all the important lettered sections. Very unique, but not my thing.
By the way, has anyone noticed the casing is crudely fitted around the MIDI ports due to a couple of poorly positioned screws? Looking up from below, the plastic is flexed slightly out of shape to pass over them. I thought mine was messed with at first until I realized it's just poor design.
I wouldn't dare spray any kind of paint anywhere near my synthesizer, but there's this great glitter paint that comes in squeeze tubes which can really brighten up the An1X. I also have some cool alien stickers. Don't cover up the writing.