It's a tricky one, I'm more intrigued with how this feud and match will play out, it's tv Gold at the moment!
Maybe rather than yet another rematch, a "Super" tag bout at Summerslam could work. Turn Undertaker heel, put him back with Kane, having them get the tag straps, go through the rosters destroying everyone, putting Triple H out of action for a month, have Triple H return with the help of a friend aka the Sledgehammer, even though everyone else is expecting HBK, tease his return for a bit before eventually doing it and having them face off at the big PPV. I'm no fan of bringing HBK back for yet another match with Undertaker. The original Trilogy in the 90s was great, the match at last years Wrestlemania was a classic, end it at this year's show, go out on a high with it, don't milk it anymore, singles wise anyway.