But I was wrong, as Acts 2:41-47 clearly shows:
41 So those who received his word were baptized, and there were added that day about three thousand souls.
42 And they devoted themselves to the apostles’ teaching and fellowship, to the breaking of bread and the prayers. 43 And awe came upon every soul, and many wonders and signs were being done through the apostles. 44 And all who believed were together and had all things in common. 45 And they were selling their possessions and belongings and distributing the proceeds to all, as any had need. 46 And day by day, attending the temple together and breaking bread in their homes, they received their food with glad and generous hearts, 47 praising God and having favor with all the people. And the Lord added to their number day by day those who were being saved.
By Acts 4:4 the mega-church has grown to 5000 men, plus women and children, and is described in ideal terms in Acts 4:32-35
32 Now the full number of those who believed were of one heart and soul, and no one said that any of the things that belonged to him was his own, but they had everything in common. 33 And with great power the apostles were giving their testimony to the resurrection of the Lord Jesus, and great grace was upon them all. 34 There was not a needy person among them, for as many as were owners of lands or houses sold them and brought the proceeds of what was sold 35 and laid it at the apostles’ feet, and it was distributed to each as any had need.
Even in Acts 5:14 growth continues. "And more than ever believers were added to the Lord, multitudes of both men and women." And Acts 6:7 says "...the word of God continued to increase, and the number of the disciples multiplied greatly in Jerusalem, and a great many of the priests became obedient to the faith."
This last reference is fascinating, because the growth that Luke highlights here is not so much numerical growth as growth of "the word of God".
So I am going to eat my words here, thanks to Michael's observation. I am aware of one successful megachurch in the Bible. It grows solely in response to systematic biblical exposition (the Old testament, to be precise), highlighted by Luke's editorial comment of Acts 6:7 that "the word of God continued to increase." The sermons we are aware of are all, without exception, expositions of Old Testament texts (Acts 2:14-36, Acts 3:12-24, Acts 4:8-12, Acts 4:23-31, and the longest one of all, Acts 7:2-56).
This church lasts until Acts 8:2, when it is disbanded by persecution. Nothing like it arises in the rest of the New Testament.
So I am forced to reconsider my earlier suggestion. It is possible for a church to grow to greater than 1000 and not be of the anti-Christ. Such a church will be founded only and solely on systematic exposition of the Old Testament, to which we can add the exposition of the inspired New Testament texts.
Car parking, comfortable seating, good toilet facilities, a well-run creche, a large building, and music of any sort would appear to be optional extras. Social welfare programmes are advisable.
And if God decides not to repeat the one New Testament example of a mega-church that we have in our present church experience, then our answer is to be thankful for what God has given us, keep preaching his word, and wait patiently for the mega-church that goes under the alternative name of "the assembly of the firstborn who are enrolled in heaven" (Hebrews 12:23)