Custom Knife Handles
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Bladeforums had this discussion on PA knife makers in 2007. http://www.bladeforums.com/forums/showthread.php/482356-Custom-knife-makers-in-Pennsylvania. I suspect those people will mostly still be in business. Many woodworkers in your area could do it as well. If you want some of the various composite materials then the woodworker should have respirator equipment.
If you have some basic equipment, you could take on the task yourself. Pick up some scale material from a place like www.texasknife.com They'll also sell you adhesives too, but even Home Depot carries some super epoxies.
Maybe contact Mike Stewart at Bark River Knife and Tool. He's done some knife rework for me before on knives he didn't even make.
I'm a fan of cocobolo. I like the color, warmth, depth and grain. It's fairly oily so is suitable for kitchens. African blackwood is good in its natural state for kitchen knife use, but I think it's kind of boring as wood goes.
I also like spalted maple or birch but this is usually stabilized (resin injection for stability/strength). Similarly, buckeye burl, ironwood, snakewood are beautiful, but usually are stabilized.
Wa, or Western style handle? I like desert ironwood personally and amboyna burl is very nice as well. I've made handles out of many different varieties both stabilized and natural. Check over at KKF - http://www.kitchenknifeforums.com There are a couple of vendors who deal in knife handle wood. And there is ebay.