Need source for composite thumbhole stock. Aby help will be appreciated.

Not sure if this is what you are looking for but it is worth a look.

http://www.rifle-stocks.com/sporter_hunting_styles.htm

Lone Wolf makes a fiberglass thumbhole stock but I have no experience with them.

McMillan makes one for Lazzeroni that they sell to the public...think it's only for the Rem 700 but not sure.

MPI also makes a thumbhole model.

McMillan is of course the top-of-the-line!

http://www.bellandcarlson.com/

I've put a B&C Premier Thumbhole Sporter stock on my Remington 700 BDL/7mm Rem.Mag.
It's nice.

One thing about using thumbhole stocks or pistol grips on rifles or shotguns that the detractors of this style of stock may not have considered is the comfort provided by the angle of the grip.

My job has taken its toll on my hands in the form of arthritis in the thumbjoints.
The thumbhole or pistol grip is very comfortable for me to shoot.

This place is full of opinions, but, regardless of what some may say, I have a reason for using this style of stock on some of my firearms because it works for ME.
Good luck.
The Bell&Carlson stocks and service are excellent.