I think it is most excellent that mega churches should exist, however think of it as a spider plant, (shown below)
There is the mother plant which is well established and well nourished, this is the mega church, the life and basis of that church community, from where all gather and learn from. Then there are the off shoots, these are the cell and salt groups that are still connected to the mother plant (mega church) but recieve nourishment and teaching from the mega church. Also the channels are open for people to go from the mega church to the cell groups and vice versa.
Should it happen that a gardner would choose to disect one of the off shoots and grant it its own soil that would be the same as establishing a new church from the Mega church, a branch of the ministry and a soon to be growing church which in time may become another mega church.
It will govern itself seperate to the church it came from yet still remember its roots (no pun intended).
This is how the church should spread.
As for food courts and stuff.
I am all for it!
It is great that people should choose to come to a church which is no longer some sort of dismal imposing hall which the elite few go to (sorry but that is an outsiders view of many churches).
Let us connect our churches to shopping malls, multi story car parks and build huge auditoriums for them.
In my city we have the perfect building which could be used for a mega church. It is called the guildhall and in it it contains a theatre, a concert hall (round auditorium), a shopping mall underneath, it is attached to the bus station by an underground link and a multi story car park, it also has two restaurants and any bars.
I know it serves its purpose as a municipal building but it would make the perfect building for a church, what more the actors changing rooms and stuff could be used for cell group rooms.