I've stippled my own weapons before. I'm not very artistic so it's not exactly pretty but it works. Just takes a steady hand and a sod iron. I practiced on a magpul grip and pmag before I did a handgun...that was before pmags were worth $100 bucks lol
Get some sticky tape that skateboarders use. Stippling your own gun is surefire way to turn a $500 gun into a $50 gun. Lots of gun shops and online vendors sell sticky tape kits. Lots of IDPA shooters use the sticky tape kits.
Or just but one of those Pachmyer(sp?) rubber pistol grip sleeves. I bought two for my pocket rockets, I think the small ones were $8.95, might run you $20 for a full size sleeve. Beats hell outta doin' $100 - $200 worth of damage to yer piece.
I have done a few things and they always turn out great, however some of them were so rough that if you didnt wear gloves it literally shredded your skin . so on those items I have taken a small piece of emery cloth and taken some of the edges back down it almost gives it a rubbery feel . Its not hard to do but very time consuming