I remember watching Jonathan Miller on TV, years ago, talking about how his consciousness gradually came to include the rear corner of his car, so that he could reverse park more effectively.
It seems that we now have experimental evidence that when using tools our minds adopt them as temporary bodyparts.
In order to help technicians, especially those with demanding dexterity requirements (such as astronauts on spacewalks) today’s invention is flesh coloured tools.
The idea is that the brain will adopt these items more rapidly and completely if the visual system sees them peripherally as not physically separate.
There would be a range of spray-on skin shades (and masking patches), allowing an individual to colour their entire toolbox.
This is related to these phantom limb phenomena too:
http://www.ted.com/talks/vilayanur_ramachandran_on_your_mind.html