Not that I've heard of. It would take more that just a stock. The mag/triggerguard would have to be cut down. If you wanted it to still be a repeater, say two or three shot, special work would have to be done. Actually, I'm not sure you'd really have room for more than one extra round with the mag cut flush with the bottom of the stock. If you would be satisfied with a single shot, after the mag housing was cut down, a filler block of some sort would have to be fabricated. That wouldn't be too difficult. Making it look good may be problematic. If you've seen any of the Chinese/Japanese/American modified ones you'd know what I mean. That trigger guard with the mag housing cut off kinda looks like crap.
Yes, there is a lot of room for thought on this, Reshaping the guard would not SEEM to be too difficult. I would have to be satisfied that mag. capacity would be 3 rounds. Anything less would not be worth the effort.