I just recently did this research as I was looking for the same thing.
I called Pendleton, Banser, Brown, MPI, Wildcat Composites and also explored the websites for Greyboe, McMillan, Manners, and maybe a few others.
From the research I did and the conversations I had, the only options for an aftermarket left handed X-bolt stock are MPI, Pendleton (Oregunsmithing), McMillan and Boyd’s. Banser will do it, but for a price of $2K.
If you are looking for something lightweight you can cross Boyd’s off your list. If you are looking for something ultralight you can cross off McMillan as they only have one style of stock which is either the Game Scout or Game Warden which comes in around 29 ounces. Both MPI and Wayne at Oregunsmithing said they could create a stock for an LH X-Bolt for any desired weight.
I then began researching MPI and Pendleton (Oregunsmithing) stocks and talked to several people both via private message and/or over the phone and I received both positive and negative feedback about both companies from people who owned the stocks. With either company I’d be spending between $700-$900 for a stock, which would almost be the price of the rifle.
I haven’t decided if I want to go the route of an aftermarket stock yet, However, after doing the research I decided if I were to move forward I’d probably go through Rick Steinhour at Extreme Rifle Works and have him buy a blank from MPI and he’d inlet it for the X-Bolt. According to my notes it would be between $700-$900.
If you’d like to read a thread about MPI vs Pendleton you read this.
Does anyone have both a Pendleton and an MPI stock or compared the two? I'm considering getting one of these and it seems that they are comparable in weight, styles, and price. MPI offers a really, really lightweight stock (10-12 oz.) but I'm not interested in a super light stock, but more...
www.24hourcampfire.com
I hope this info helps you. Please keep me posted on if you decide to move forward with a stock. I’d.be interested to hear how it turns out.