"In a temple recommend interview you are asked if you sustain the leaders of our Church. If you disagree with the Church on Prop 8 then you cannot answer yes to this question."
I do sustain my Church leaders both high and low. When asked in a temple recommend interview if I sustain my leaders, I can unquestioningly answer yes. To sustain them means to acknowledge and uphold their divine calling. I do that. It does not mean to accept every word they say. It does not mean to think them infallible, nor does it mean that we have to do everything they ask. As mentioned before, concerning Prop 8, Elder Clayton said that "Latter-day Saints are free to disagree with their church on the issue without facing any sanction."
Finally, some quotes for thought:
"Do not, brethren, put your trust in man though he be a Bishop, an Apostle or a President; if you do, they will fail you at some time or place; they will do wrong or seem to, and your support be gone; but if we lean on God, He never will fail us... When men and women depend on God alone and trust in Him alone, their faith will not... be shaken if the highest in the Church should step aside ... Perhaps it is His own design that faults and weaknesses should appear in high places in order that His Saints may learn to trust in Him and not in any man or woman." - George Q. Cannon
Or Brigham Young:
"I am more afraid that this people have so much confidence in their leaders that they will not inquire for themselves of God whether they are led by him. I am fearful they settle down in a state of blind self-security, trusting their eternal destiny in the hands of their leaders with a reckless confidence that in itself would thwart... Read More the purposes of God in their salvation, and weaken the influence they could give to their leaders, did they know for themselves, by the revelations of Jesus, that they are led in the right way. Let every man and woman know, themselves, whether their leaders are walking in the path the Lord dictates, or not. This has been my exhortation continually." (Journal of Discourses, v. 9, p. 150)
"How easy it would be for your leaders to lead you to destruction, unless you actually know the mind and will of the spirit yourselves." (Journal of Discourses, v. 3, p. 45)