I guess the main issue is how to get people in the right servers at the right time. Also would it be EU or NA (or both?). I think the easiest way to reach as many jumpers would be to make a steam group for it. Maybe also post about the new group in a couple of the other large steam groups like TF2RJWeekly.
I think this is a great idea, but to set up something like this and keep it working takes a lot more time than you might expect. It's gonna be important to promo it, so definitely make a thread on the tf.tv forums and maybe contact TF2JumpAcademy. If there's an easy system to sign up (google form) and maybe a couple of divisions for different experience jumpers it could be a pretty sweet weekly event.
Regarding the format though, I think having only 2 jumpers at a time would be a little boring, maybe larger groups (4 or 5) would be a bit better suited. Top 2 move on to next round, second 2 to loser's bracket, and last place just SOL.