I just got done making four different threshholds for my flooring project. Since I was installing hardwood, I just made them from leftover pieces of the flooring. But since you have really thin stuff, I would just cut down a piece of oak like mentioned above and stain it to match. If you have a router, you can round over the edges a bit. If you don't have any equipment to do that sort of thing, go visit the wood trim section of your closest big box store. I have made threshhold out of door jams and other pieces of trim that I simply had to cut to length and stain.
