The populist interpretation of Penal Substitution, that in order to forgive us God needs blood and so He makes Jesus the cosmic whipping boy to receive the punishment that we deserve is not, in my mind, reasonable. On the contrary, I believe that what it ultimately says about God and His justice is abominable. But then I wouldn't call it mainstream, I call it fringe; simply on the basis that this isn't what the majority of Christians believe, neither historically nor presently--this is not the belief of Roman Catholics, Eastern Orthodox, Oriental Orthodox, and other historic traditions; and its place in Protestant traditions is also, I'd argue, losing a lot of sway--particularly among Mainline Protestants who typically find the older views such as Christus Victor and Traditional Satisfaction far more meaningful and true.
I'm hardly as alone in my thinking as you think. The views I have exist precisely because of my study of Church history and the diversity of views found across numerous denominations and traditions; through discussion with Catholic, Orthodox, Lutheran, Anglican, and other Christians and attempting to reach a view which I believe is historically orthodox, in line with the teachings of Scripture, the ancient fathers, and the historic consensus of the Christian faith.
-CryptoLutheran