OK, so I'm going to reference Poker Shares for this question. They depend on being able to accurately answer this question to make money.
They don't have any $10k events listed at the moment (but keep a look out for next time they do!). They have a €25k high roller, and the best players in that are reckoned to have a 29% ROI. Meanwhile Daniel Negreanu reckons he has a 280%-300% ROI for small buy-in events (and a 450% ROI in the main event!).
So $10ks? I've seen some tough $10k fields, where I would expect the best ROI to be no more than ~20%. Meanwhile, there's the main event. So I don't have a good feel for a "typical" $10k ROI. Finger in the air guess, I'd say if the best players are managing 29% ROI in high-rollers, 50%-60% should be achievable for the same players in $10ks on average.