I'd be down for it as an early precursor to a feud, say Austin mentions how the two have been compared and he's disgusted by that as he'd never back down from a fight. Austin turns and is hit with a GTS as Punk stands over and shouts at Steve how he's never turned his back but now he's flat on it. Austin disappears until after the rumble bar 2/3 mini appearances to brawl abit with Punker before he takes an injunction out on him, speaking about how he and Heyman believe they needed to protect Steve from himself and stop him getting another beating. Punk keeps hold of the title and feuds with Rock at RR, beats him in the match then beats him down post match, Austin returns the next night after Punk brags about ending the great one. They brawl again and Austin gets the upperhand as Punk bails, Austin gets the mic and cuts a promo about always being anti authority so as he was sat at home he was thinking why should he listen to this bit of paper in the restraining order he then tears it up and says he's been signed back to a one match deal with Punk at WM, if he wants respect he has to beat Austin to get it. Punk refuses and leaves the arena, fast forward to Elimination Chamber, Punk is about to beat his last challenger. Just say it's Bryan, Austin runs through the crowd and steals the key from a nearby ref and beats him down before charging in and stunnering both men before sliding out and taking a chair and beating Punk with it, shouting "You're gonna go one on one with old Stone Cold". Punk agrees to the match after losing his title, they wrestle at WM with Punk going over after 2 GTS and kicking out of a stunner.
I know it'll never happen as above for various reasons but if on the odd chance they did start a feud from it, I'd be cool with him going and leaving.