Just wanted to chime in as one of those elders you talked about. I was part of the Mars Hill church plant. And I am currently working with my 2nd church plant in Russia. I want to share some thoughts on how it has been for me as CCC staff to be in these roles as founding elder/church planter and being full time staff.
In 1995, when we planted Mars Hill, I found it the ideal position to be in to help plant a church as I would be interacting with a host of potential church members on the campus of the UW. I was also able to help steer the direction of the church by being on the elder board and, through prayer and counseling, able to contribute to the spiritual growth. However, I constantly was stressed with the fact that there was so much more I wanted to do for the church but just didn't have time. I saw that Mark was max'd out so much of the time, but I could do very little to lighten his load. I remember asking him one time how I could be of greater help and, knowing my commitment to CCC, he told me, "Just bring more people to church, that's all". So I did. But there was always that tension in me.
Fast forward to Russia. When I left Seattle/Mars Hill in 1999 to do college ministry in Russia I knew there would opportunities to plant churches there. In fact I have been able to take part in 2 church plants, both from scratch with almost no official ties from the west. This has been a challenge but also a blessing as I've seen local people step up and lead. But again, the tension is still there, always wanting to do more for the local church. But every time I go to church and see the college students there I realize that, as long as I am here, my main contribution will be to bring people into the church. Of course I also sit in on elders meetings and counsel the younger leaders. But I take more of a back seat role in things. It is humbling, but it is where I know I need to be for now.Who knows, maybe someday we might go full time into church planting. But for now and for the last 10 years, I dont regret being in that tension of taking part in something great (church planting) but also wanting to do more, realizing that God places others around me who step up.