I am glad, cubanito, that you and your wife were able to come to an aggreement on the use of such a procedure. I too will be pursuing said procedure in the very near future.
Many people would disagree with you on your stance that vesectomies are "for the most part irreversible." Check out some of the testimonials on vesectomyreversal.net for more information.
As you and I have both stated, we don't believe getting a vesectomy to be immoral. I also believe that non-abortive contraception is definitely an option for Christians. Where TwinCrier and I, and I assume you, disagree is with the application of the convictions that have been displayed. This situation could be compared to someone getting some sort of piercing. After days/months/years of having the piercing that person becomes convicted that they should no longer have that piercing. Should they take out the stud or leave it since it was already placed there years ago?
This does not change the initial reason for the vesectomy. If there is such a strong conviction about contraception, they should be encouraged to not "keep wearing the piercing" and get the procedure she finds a sin reversed.