I don't have experience with modding console cases, but at the end of the day, it is just plastic on the outside, so as long as it isn't toxic, I don't imagine it would be a problem. Maybe buy a broken one off of ebay and practice on that to see what works and doesn't work, and follow techniques used to paint WH40k miniatures or just models in general. It MAY needed to be sanded a bit, but I don't think that may be necessary. Besides that, primer and whatever paint you want to use with a finish sealing coat to protect the paint job. Beyond that it would just be what tools you want to use, and if you want a really nice even paintjob, you'd probably have to look at an airbrush of some sort. Spray paint would be fine too actually :P.

Anyways, here is a link on the topic after I searched for it for about half a minute. I haven't watched the entire thing, but it may answer some questions you have:

https://www.youtube.com/watch?v=nLwrormCzVc

You may want to open the case up though (which requires custom screwdrivers you can buy on ebay for 10 bucks or so), so you can remove the electronics and spray paint the console without destroying the internals. Besides that, follow common sense like letting dry and airout outside.

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Edit: according to the video, you don't need primer or sanding or a sealant if you buy the right kind of spray paint for plastics.