I looked into this in the past, as I briefly was interested in the Tikka T3's since they make LH models. Unfortunately, I do not know of any American stock making companies that are making production aftermarket stocks for the Tikka rifles. I checked all the low-end companies like Hogue, and even high-end makers like McMillan, and no one I could find was making anything. You can probably find someone who could take a generic stock and custom fit it for you, but you will probably not appreciate the cost, it'll be at least what you paid for the rifle.
Just to follow up on that last suggestion, there's someone you might contact just to see what he could do. Call Kevin Rayhill of Stockade Gun Stocks
, and see if he could custom-fit one of his stocks to a Tikka. He just did some customization work for me on a Savage, and does very nice work while still keeping the prices of his stocks at least within the lower stratosphere. He may be able to custom-fit one for you, or point you to someone who can.
Good luck and hope you find something, they do make nice rifles!