I'm not really talking about a 'kit' per-sa but vinyl is pretty easy to come by.
is a great resource...a few people on other forums have used them with great success.
This guy, I found on this site has awesome graphics for the adventure: http://crispydesigns.co.uk/
Make sure the surface is clean, lay the vinyl, pull it, use a little heat, cut it, have fun it with it. Its pretty hard to screw up and if you do, you pull it up and lay a new sheet. I believe you could do an entire bike for less than $100.
When you scratch it, you just simple either cut it out and put new vinyl down or put a piece over it.