I have observed two methods of church planting, both of which have something to commend themselves to us. The first method is practice by Sovereign Grace. They have folks pray about being part of a church plant in another city, sometimes in another state. Those folks then join the pastor being sent out and get new jobs, relocate to the new city and put down roots. This way the new church starts with a core of tight-knit people that are on the same page.
The second method is that of the AMiA parishes in the D.C. area. The mother church has planted two churches in two years. Rather than becoming a mega-church, the mother church hives off when it hits about 250-300 people and starts a new church in the area where a big cluster of current attenders live. The mother church had 3-4 full time clergy and sent one guy to plant each of the daughter churches. The pastors can also rotate in and out and preach at the other parish. This model is also effective, logical and preserves a parish mentality.
The things I don’t like about the Sovereign Grace method are that Sov Grace seems to have no problem with mega-churches. Their churches get huge and lose intimacy and real relationships between all members. They seem to be too slow to ordain men, so they don’t have a huge base of guys to launch multiple local works. They also don’t seem to want to do multiple local works – at least not to date. They seem more inclined to launch in new cities or states rather than to hive off and establish tons of local works that reach the same region/city.
Perhaps combining these two methods would be good. Rather than sending 30 families to a new state, the parish could send 30 families one suburb away. That would make ties to the sending church more effective, but might decrease the sense of mission that the new work has in that the people are still in their comfort zone to some degree.