Are you looking for characters that have hair like this, or general advice? I can only help with the latter, really, but here goes.
I was active in the cyber/industrial scene back when dread extensions and falls were becoming popular (showing my age ohhhh) and I remember a few rules of thumb (keep in mind that some of these may have changed over the years...I'm talking about a decade ago).
1) DO NOT IGNORE YOUR HAIR COLOR. Nothing looks worse than seeing black and blue falls on someone with medium brown hair...it just seems lazy. If your hair is not the color of your ideal synthetic dreads and you can't use temporary dye, get falls that are predominantly your natural color (I'd say at least 75-80%) and think of the other colors as highlights. Trust me. This was my biggest pet peeve.
2) Your hairline. Bangs are the best option, IMO. This is not a requirement, but it'll really make everything look more polished. You can buy a clip-on fringe for this purpose. Leaving a bit of long hair loose is fine too, but having all of your hair pulled back ballerina-style is not going to look good...it's just going to draw attention to the fact that your hair is not naturally dreaded. And yes, 90% of the time it's not naturally dreaded, but still, you want to maintain that illusion.
3) It's easiest to attach falls to longish hair that's been secured in a bun or buns, and it's best to use lots of product to keep those buns in shape (though make sure that they're flat enough or your falls are thick enough to keep them hidden). If you don't have longish hair, be prepared to use a lot of bobby pins (and if your hair is particularly short, a lot of elastics will help by giving the safety pins more to grab on to). Alternately, putting it in a few braids rather than a bun can add some interesting texture. If you leave your hair loose, it might get tangled up in the falls, and either way, it'll look unfinished.
4) Don't go too thin. Falls look best when thick (I personally like them shoulder length, but this is true for long falls as well). I know it's way cheaper to get fewer dreads, but it looks worse in the long run--both more fake and more unfinished.
5) If you are going for a cyber look, smooth dreads are the best way to go. I liked mixing in some rexlace and other plasticky things (old-school spiral phone cords are fun). If you are going for an industrial look, it's better to try for more natural looking dreadlocks. This doesn't mean no pretty colors...it just means flyaways, etc. Very clean color spiraling (and very clean anything, really) fit the cyber look way better than the industrial look. For me, this was easiest to think about in future terms. If you're going for the industrial look, you want to make it look like your hair's survived the apocalypse. If you're going for the cyber look, you want to make it seem like your hair is fresh out of a fancy, colorful, more utopic future...the kind of pixelpunk future that the 80s was so fond of.
If you want your look to seem unified and polished, it's important to distinguish between these two styles...they can both involve dreadlocks, but they're not mix and match. Try to choose clothing accordingly. XD
I hope that long rant helped, and like I said, this is all based on my personal experience in a pretty distant past and things may have changed a lot since then.
Last edited by uncompassed : 09-30-2010 at 02:16 PM.
Reason: Correcting typos, adding a bit more info.