Have you checked for a replacement at Midway???
What you are doing is really cool for your nephew. I would check midway.com I thought that they offered fajen stocks as a drop in replacement. I just lost my Dad about a month ago and I am looking forward to getting his Remington 742 and Winchester M12 out for some range time when I get them up here from Florida. I know that he will be watching as will your brother when you get his M700 out for some fun.