1) CDNN always has wooden ones, siles, herret, sometimes factory I think.
2) Cheaper than dirt always has lots of rubber ones under $20.
3) for nicer wood or custom, check ahrends, spegel, eagle, etc. Laminate ones from Ajax, altamont.
4) dont' forget the factory web site, they have some custom things there and a few aftermarket ones, as well.
5) don't forget a tyler t-grip with factory stocks is very comfortable, too.