Being a newbie customizing a knife, a Dremel is probably the most valuable single asset to have on hand. I've used mine to reprofile blades, and cut, polish, grind, create, and destroy, just about everything I've been able to get my hands on. My "Dremel" is actually a Black & Decker Wizard, but it's basically the same thing, totally compatible, etc. Make sure to get one with variable speeds, mine has numbers but not RPM indicator, so I have no idea what speeds it goes.
A few tips I've picked up - always wear eye protection, because dust & sh!t do go flying. Get some kind of dust mask so you're not breathing it all in. Whatever you want to do to one of your good knives, try it first on a POS knife; if you don't have a POS knife, it will be well worth what it costs; you will learn enough on your practice knife not to screw up a good one. You can do a lot of damage really fast with a Dremel. eBay &
www.widgetsupply.com are a great source for bits & attatchments, much cheaper and larger selection than Home Depot.
If you do a search on "Dremel," including the archives, you'll pull up dozens of threads with lots of ideas and stories of what other forumites have done.