Shad I could post numerous scriptures that show repentance as part of, and a very important part of the equation. You see, even to go from a non-believer to a believer, you must have repented. Repentance cannot be taken out of the equation. It means to simply change your mind about something, to turn to God is by definition, repentance. To turn from sin, is repentance. To go from not praying to praying, is repentance.
And if you read verse 29 in the context of Romans 11 you will see that the gifts and calling of God are without repentance. That's the gift of grace, the gift of righteousness, the gift of the Holy Spirit, the gift of eternal life and the gift of His Son who called us according to His grace without repentance.
Are you going to take that out of context and go to some commentary that interprets that in some abstract way to suit your belief system?
I consult commentaries because I am humble enough to admit I don't have the answers from my own private reading of scripture, particularly on difficult matters. Here's what Barnes has to say, and I highlight in bold a very important statement which counter-argues what you said:
Without repentance - This does not refer to man, but to God. It does not mean that God confers his favors on man without his exercising repentance, but that God does not repent, or change, in his purposes of bestowing his gifts on man. What he promises he will fulfil; what he purposes to do, he will not change from or repent of. As he made promises to the fathers, he will not repent of them, and will not depart from them; they shall all be fulfilled; and thus it was certain that the ancient people of God, though many of them had become rebellious, and had been cast off, should not be forgotten and abandoned. This is a general proposition respecting God, and one repeatedly made of him in the Scriptures; see Num_23:19, "God is not a man, that he should lie; neither the son of man, that he should repent: hath he not said, and shall he not do it? hath he spoken, and shall he not make it good?" Eze_24:14; 1Sa_15:29; Psa_89:35-36; Tit_1:2; Heb_6:18; Jam_1:17.
So in light of what this trained theologian says, you must admit you have taken that verse out of context. The funny thing is most of what people disagree with me about in here, including yourself, I have taken from reliable protestant theological sources from the past hundred or so years. That you disagree with it shows how far Christianity has declined even further into deception since the reformation. The guy I quoted from above was an American presbyterian minister and theologian who lived in the 17-1800's. But you treat my views as if I am quoting from Mormons or Catholics.