I think antes are your answer. They are common is most tournaments. We have 5 weekly tournaments and the only one without antes is the bounty touranament.
As for players sitting out let me point out some things I have obseved.
Phil Helmuth arrives late to every major touenament he plays in.
Phil Laak was sick on his day one of the WSOP Main Event one year. They would not allow him to start on another day so he tripled up quickly and went to his room. HBe was blinded out
for the rest of the day but he still had a respectable stack when his day 2 came around and he was feeling better.
In the 1990 WOrld Series Main Event, Stu Ungar did not retrun to the table after the 3rd day due to illness but his chip stack still made the final table and finsihed 9th and in the money.
I know it seems insulting to the other players to not play and let your stack coast into the FT but neither will these players ever win an event since they handicap themseleves by not building their stacks and equiping themselves for the final table battle.
Add you antes at the point whne the BB is 100, start with 25 dollars and increase every level 25, 50, 75, 100, 200, 300, 400, 500, 600, 800, 1000 2000, 3000, 4000, 5000, and so on.
You will here some complaints from some players but the tournaments will also play quicker. Wxplain that you are structuring your tournaments to match the big ones.