Some children don't respond to rewards, treats, etc., for them the biggest incentive IS being potty trained. My guy (28 months) responded well to stickers for a few days for peeing, then Dum Dum pops for pooping, now it's just the "high-fives" and praise for both. Chuck E Cheese possibly came too soon and too easily for your son, I've seen it recommended you use a chart and when they do it 10 times, then they get the big reward. An incentive has to be meaningful to that particular child, something he or she really wants on their own, or it won't work long-term. Something like pre-school, a new toy, something he or she is begging for and will work for. But at this point you need to change your method as rewards haven't worked.
I read something about a month ago that may help. We're using cloth trainers, not pull-ups, so I can't personally vouch for it's success but it seems many do. It also seems it would work since it's his body that he is controlling and he would still be doing that with this method.
Give your son a pull-up and allow him to poop in it, BUT he has to sit on the potty or on the toilet to do it. Handle it matter of factly, no rewards or praise at this point when he goes, just "Oh, you pooped, good. Here's some toilet paper to clean yourself, I can help if you need me." He puts the poop in the toilet, he flushes it, throws his own pull-up away and washes his hands, you're putting the responsibility on him. Of course you can follow-up to make sure he's clean.
Once he's doing this regularly and easily, I think the article mentioned a week or so but you could decide this, you (without his knowledge) cut a hole in some of the pull-ups so that when he pulls it up and sits on the toilet his poop will go fall into it. When he's done you tell him, "Hey, you pooped in the toilet." No fanfare still, just matter-of-fact, because he's still pooping in a pull-up. Of course, he continues to wipe himself, flush, toss the pull-up and wash his hands, so he's learning the going potty process..
Then, once this is second nature to him, one day you don't have any more pull-ups (you don't buy anymore and you have hidden his sister's diapers where he absolutely cannot find them) and he has to poop without one. When he does this willingly you then praise him abundantly and tell him "You pooped in the toilet, great job! I'm so proud of you!" THEN if you wish to treat him to something special you do it, but you may want to wait a week or so to make sure.
I would recommend once he's going on his own with no problems you continue to hide sister's diapers, he sounds smart and there's no reason to tempt him to outsmart you again.
And for moms whose little ones are using diapers to poop in this would work as well, just cut a hole in the diapers.
Hope this helps! : )