Because Venturing is such a different animal then the CS/BS progams, it would be in your best interest to have a different event for the venturers. If you really want to include venturers in the camporee, you could have some of the crews get together and setup 1-2 stations for the scouts to visit.
If you decide to have a seperate event, do something that the venturers want to do and get input from the venturers themselves. Just because you think it would be fun, doesn't mean that they will. (I have a feeling that this will be a problem in the next few years with the one senior scouting activity, only one person who is activly on the committee is actually a Venturing leader and they want to change or replace activities) Some activities that we do at our event include volleyball, swimming, talent show, luau, dance (since this is coed), and my favorite canoe swamp (tie two canoes to stationary objects so that they are about a foot apart. three people get into each canoe. everyone is given a bucket. when the whistle blows both teams try to sink the other teams canoe by throwing water from the lake into the other canoe. you cannot bail out of your canoe). We are talking about trying a mini triathlon next year also.
Hope this gave you some ideas of what you could do for a ventring activity next year. Just remember this golden rule: Do something that the venturers want to do and probably get them to help plan it (also, just because cub scouts and boy scouts enjoy doing X doesn't mean that venturers will also enjoy doing X).