I recently did that to mine. My teak liners were badly damaged, with some delamination, but mostly cut up by years of adding and removing stuff by PO's. So I cut new liners out of Okeume 1/4" ply, 1st coated in a few coats of epoxy, then painted with a barrier coat, and finally painted with interlux brightsides flattened down a touch.
I also added puck lights (with a mohogany base of my own construction since I wasn't willing to cut into the Balsa so they would fit) mounted to the roof liner just above those panels, with a red bulb for night adjacent to bulkhead, and a white one about two feet back, same on port/stbd. On either side of the companionway underneath the matching cabinets (one for radios/iPod/Binocs, and the other for Sunscreen/Spices - built as a polygon so shelves are level - fun!) I mounted a 2-position nav dome light which also allows for red night lighting. The night lighting is really quite nice, and the ambiance is very relaxing while anchored or docked at night. It is also great for our 18 month old who is set up for sleep in the main salon when we have to move about.
Anyway, I like you, am inspired by Martin's achievements, and plan to continue making some improvements. Below are some pics of my interior work, as well as some salon hatches I recently built that are being fitted into place (no lens installed yet, nor are they fastened to the hinges, but you get the drift...)
Best of luck with your projects,