Sorry it took me a while to get back to this Chad. Making liners can be pretty simple (and very difficult), depending on the materials you use.
The basic premise is that you choose your material, trace out a handle on it (twice), then cut the profile out with scissors or snips of some sort, and drill your bolt holes. I like to drill the bolt holes through both liners while they are taped to one scale, so you know you are getting a good alignment when it's all done. Then, depending on your material, you can work the liners down until they match the shape of the scales and have nice smooth edged. With easy to work with materials (5-star notebook / folder cover material, thin cutting boards, dvd cases,etc), just sandwich the liners between your set of scales (I have one set just for this, so the one's on the knife stay nicer). Bolt the scales together with the material in the middle and make sure the scales are lined up with each other. There is some play in the bolts, so this is important. Use a razor knife (the snap-off blade kind works well here) and slowly work the material down without gouging your handles. Once everything is smoothed down to the handle you can install it all or give the liner edge a quick sanding to smooth it even more. With tough materials that the razor knife doesn't play well with, I use a set of mini files and file down the material until it's flush with the scales. This is for things like G10, where it will not cut well or will dull a blade faster than Trade scares small children off his lawn.
After it's all done, you can just bolt everything to the handle or for a really good fit, glue the liners to the scales with CA glue. If you want a good source for the really thin G10, shoot me a pm. Otherwise, the other materials can all be had by cruising the aisles of your local Wally World / Target stores.