Raising forever with the second nuts

$5-$10 Limit game with a full kill and its a $10-$20 kill pot. I've just sat down with $300, and the villain in this hand has about $200. I'm dealt QQ in mid position and raise two limpers. The flop comes Q-8-8 and I've flopped the second nuts. My opponent bets out I raise and he calls. Turn is a blank and now it gets interesting. He bets, I raise, he reraises, I rereraise, he goes again, and at this point I just look at him and ask him "Do you have pocket 8's?" He shakes his head No and I believe him, so I raise again, and he pops it one more time all in as he is holding Q-8, which from his perspective is also the second nuts. Now I suppose he never thought I was holding queens full of eights until I turned my cards over-- but I really wonder how long the heads up raising would have gone on had he (and I) had really deep stacks....