Don't worry about replacing the kebob keeper, they just are in the way most of the time any way. Just lay your kebabs on the grill, it works, trust me. Before you go whole hog into smoking, you'll need some wood chips. Decide whatever type of wood you want, apple or alder work well with chicken. Purchase some wood chips, not chunks, chunks are much larger. Take some aluminum foil and make a pouch to put the chips, that you have soaked in water, after the water soaked chips are in the pouch, take a fork and make several punctures in both sides of the pouch, lay the pouch on the grill over the burner. As the pouch heats it will generate smoke, but should not catch fire, if it does catch fire turn the fire down, and squirt a bit of water on the pouch to extinguish the fire and continue.
This method should limit your expense to just the chips, so if you don't like smoked meat all you have spent is a few bucks on the chips. If you like smoked meats, the sky is the limit anywhere from the pouch method to custom built BBQ pits that cost thousands.