Anaheim, CA
Here's my advice:
1 - Fill the scratch. There seems to be lots of advice on products already.
2 - Find a miniatures war game hobbyist to paint over the repaired area. A good miniatures painter has a lot of experience in color matching and attention to detail, and you could probably hire them cheaper than a 'professional' artist. If you have a local game store you can probably find one there, or check some online forums for painters in your area.
or - just paint the repaired area black yourself. not that hard, and it wont call attention to itself.
3 - Find a way to seal and protect the painted area. Might need to experiment with several protective coats to not get a 'shiny' snail trail of gloss where the repair was done.
good luck.
