The issue I am really trying to get at is this- if you believe that God's grace and love compels Him to not send anyone to hell forever, then is grace really grace anymore? Is grace undeserved if God by His very nature is required to save sinners from eternal torment that their sins demand? The answer I think is, obviously not. So when Rob Bell asks "Would a loving God really send billions of people to hell for eternity?" what I hear him saying is "If God is love, then God would not and cannot leave sinners in hell forever."
Note: After thinking more about Rob Bell's positions and reading some who have reviewed his new book, I doubt Rob Bell believes in penal substitutionary atonement. Bell does not seem to believe that God would pour out wrath on us at all, even though we are God-hating sinners. According to Bell it seems that hell isnt' something God sends us to, it is something that we create on our own, and therefore, Christ could not have died to save us from His Father's wrath. Clearly this leaves Bell outside of the faith and whatever he is teaching, he cannot be teaching the true gospel, which is ultimately our need to be saved from the justice and holiness of God because of our sinfulness.
Well if this is true (that God would not and cannot leave sinners in a hell-like state forever), then God is no longer saving us by grace, He is saving us by compulsion, by requirement. In other words, in some sense, we deserve to be saved, because God must save us if he is loving, according to Rob Bell. But grace by definition is never required, and God's love is never a requirement. So to say that God's love demands that He save us, Bell has just completely redefined the meaning of love itself.
What I am saying is that it sounds like Rob Bell is robbing the glory of the cross of Christ altogether. The gospel is a gospel of grace- but Rob Bell's gospel is a gospel of, basically, "God wouldn't send us to hell forever and leave us separated from Him, because He is loving, and a loving God by definition doesn't leave people in hell forever but redeems everyone eventually."
Suddenly the cross of Christ has lost its wonder, and quite frankly it has lost its very saving nature.
Bell's message seems to be "Don't worry, God is love, God's goodness demands that we be redeemed. Otherwise, God is not good. Therefore, it is a must that God saves us."
Yet if it is a must that God saves us, God is not saving us out of grace and mercy.
Conclusion: The reality of hell and the fact that God is obligated to send us their because of our wickedness and sinfulness is what makes the cross of Christ gracious, merciful, and truly loving. Rob Bell takes the love of God away, the true meaning of the cross away, and creates a God who acts not out of love, but out of obligation.
And if this is indeed what Rob Bell really means, then I say that the god of Rob Bell can go to hell, for my God, the one true God, is a God who saves sinners out of grace, love and mercy, not because He is required to, but because He wants to.