Does anyone know who sells stocks for these?I haven't found a stock supplier yet that lists them.

I assume you are looking for a rifle stock....McMillan makes them (special order but they are the same ones they sell for the Rem 700) and so does H-S Precision although they will charge you an extra $50.00. They both make and stock the pistol stocks also.

I should have clarified that, looking for the pistol stock.

I shoot my midgrip XP in 7-08,with a Fajen thumbhole laminate. Much better for me,than the issued handle. I see them for sale,in different places,now and again.

Many stock makers,cater to the XP. Are you wanting wood,laminate or synthetic?............

Western Gunstocks made a beautiful mid-grip for me.

k wood....I am in the process of turning my XP-100 into a rifle...it has a factory stock on it that I had painted primer grey in anticipation of a fancy paint job but decided to use the action for a custom rifle.
It is one of the early ones with the center grip, if you are interested let me know. I also have the .221 Fireball barrel that I don't need anymore.