I'm just getting started doing the same thing. Here are a few more online sellers:
http://www.bitsofpieces.com/
http://www.russellsports.com (need to search through catalogue)
http://www.advancemfgtech.com/ruger_stock.htm
http://www.bitsofpieces.com/
http://www.russellsports.com (need to search through catalogue)
http://www.advancemfgtech.com/ruger_stock.htm