I can think of plenty of churches that would accept Tiller in the congregation. After all, who among us hasn’t sinned?
Having said that, I think the more pertinent question would be, “What kind of church would endorse Tiller’s beliefs and practices?”
Tiller had not ‘sinned’: he was ‘sinning’.
I Corinthians 5:
But now I am writing you that you must not associate with anyone who calls himself a brother but is sexually immoral or greedy, an idolater or a slanderer, a drunkard or a swindler. With such a man do not even eat. What business is it of mine to judge those outside the church? Are you not to judge those inside? God will judge those outside. “Expel the wicked man from among you.”[b]
The leader of his church has the obligation to ask him if he endorses the sin of murder in the form of abortion, and if he affirms the sin he is not repentant and should be excommunicated.