I have a very long LOP on a 2 trigger gun- 16". Adding length will most likely give you too much DAH and almost always is unattractive. Restocking will cost a minimum of $2k and can be much more. Another option is a buttstock transplant. I had one done to an Ithaca Flues and it is superb. Can be done for $500 and up depending on wood quality. Keith Kearcher did mine.
Regards,
Jeff

"We are men of action. Lies do not become us."
Wesley