Dreadlock Extensions
Dreading Methods
yeah its a good idea for the extensions part but shes not a natural dreadhead. most of those dreadz are fake.
I highly recommend Katie's tutorial:
http://community.livejournal.com/get_up_dread_up/5324366.html
Keep in mind that the extension hair will dread at a different rate than your own, and won't have the same texture. Colour matching is difficult as well.
Commercial human hair has been chemically treated, and tends to knot up really fast and bunch up, rather than down. The extensions will start out long but will shrink & tighten into a fat mass, which adds extra weight to your dreads. That's why your own dreads have to be mature before adding extensions -- you need a solid foundation that won't unravel from all the extra weight & pulling.
I think you owe it to your client to explain all this and let them decide if they still want to go ahead. It's a lot of work, and the only way to remove them is by cutting, which will obviously affect their natural dreads.