? What exact thing exactly?
Why would they want to? They generally just finish the game under standard rules if adjournments are allowed. What would be the advantage? Why would you want to put any limit on games (e.g. the Rybka Nakamura game I showed) that are progressing?
Nobody has managed anything like 1000 moves so far, so it would effectively be a non rule anyway.
If you want to allow more moves for games that appear not to be progressing the you could use my suggestion in #447.
So they could do that exact same thing with a longer time limit. They could also do a combination, such as 1,000 moves or x hours, which ever is longer.