If you're a fan of Sin City and Machete, it's looking like it's a matter of "when" and not "if" we're going to be seeing sequels to both films. Robert Rodriguez is currently promoting Spy Kids: All the Time in the World in 4D and had the following to say about the sequels during a recent interview:
"Sin City 2 is going good, we’re just finishing the script for that, we already got the money. We have everything we need so we can just start shooting as soon as we get the pages. And it’s the same thing for Machete 2. We’ve already got the budget, just waiting for the script. As soon as we’re finished writing we get to start the shoot."
In most cases, a script will be finished and the deal falls through at the financing stages. In this case, they already have the budget in place, so we expect to see both films getting started in the near future.