This is a structure I've played a couple times now, once at the league co-hosted by @T_Chan and @Racer96, and once at @Mesnik44's Christmas tournament.
The basic idea is that there are three mini-tournaments, roughly an hour each, followed by the main event. For each of the mini-tournaments, players start with T3000, and play four 15-minute blind levels (25-50, 50-100, 75-150, 100-200). Whatever chips you have at the end of the fourth level get added to your starting stack for the main event.
If you bust out of a mini-tournament, it's not a long wait until the next one starts. Everyone who comes out gets to play at least three-ish hours of poker, plus the main event entry, so if folks are driving a ways to get there, it's worth the time investment. Latecomers can still play the main event but start with just a base stack (or the lowest starting stack, if preferred.)
For the league game we had 21 players and the main event base starting stack was T10,000. The biggest stack was right around T30k iirc.
For the Christmas game there were 19 players and the main event base starting stack was T30,000. The biggest stack was approaching T50k iirc. The winner was decided about 12:30 or 1:00 am after having started the main event about 5 pm iirc.
Some observations and/or recommendations...
1. We used different chip sets for each of the mini-tournaments, as well as for the main event. Getting the starting stacks ready ahead of time saves a bit of setup time in between mini-tournaments, as well as providing the opportunity to getmore chips moar chipes into play 
2. Tables and seating are re-drawn after each mini-tournament and for the main event.
3. We didn't bother with balancing tables during the mini-tournaments as players got knocked out. Too short to be worth the effort.
Questions/comments? Ask away! I'm planning to use this format perhaps quarterly once I start hosting again.
The basic idea is that there are three mini-tournaments, roughly an hour each, followed by the main event. For each of the mini-tournaments, players start with T3000, and play four 15-minute blind levels (25-50, 50-100, 75-150, 100-200). Whatever chips you have at the end of the fourth level get added to your starting stack for the main event.
If you bust out of a mini-tournament, it's not a long wait until the next one starts. Everyone who comes out gets to play at least three-ish hours of poker, plus the main event entry, so if folks are driving a ways to get there, it's worth the time investment. Latecomers can still play the main event but start with just a base stack (or the lowest starting stack, if preferred.)
For the league game we had 21 players and the main event base starting stack was T10,000. The biggest stack was right around T30k iirc.
For the Christmas game there were 19 players and the main event base starting stack was T30,000. The biggest stack was approaching T50k iirc. The winner was decided about 12:30 or 1:00 am after having started the main event about 5 pm iirc.
Some observations and/or recommendations...
1. We used different chip sets for each of the mini-tournaments, as well as for the main event. Getting the starting stacks ready ahead of time saves a bit of setup time in between mini-tournaments, as well as providing the opportunity to get
2. Tables and seating are re-drawn after each mini-tournament and for the main event.
3. We didn't bother with balancing tables during the mini-tournaments as players got knocked out. Too short to be worth the effort.
Questions/comments? Ask away! I'm planning to use this format perhaps quarterly once I start hosting again.