I think in some respects you have the cart before the horse. Certainly spending is a horrible problem, but the FairTax is a tax bill, not a spending bill (nor can it be). To repeal the 16th, there must be an practical tax bill in operation else you'd be exp[ecting the Congresscats to eliminate the taxes on income with no replacement - very few in Congress are THAT foolish (and if so, they deserve to be ousted).
So trying to get rid of the 16th first cannot possibly happen while once the FairTax is operating as a revenue neutral tax bill, the 16th becomes an anachronism much like the Prohibition amendment and serves no useful purpose. It certainly would be repealed in short order ... especially once citizens tasted the benefits of the FairTax.
Also, I think you missed the point that the FairTax REDUCES the costs of exports - no tax stamps required since the exports are not taxed.
"It certainly would be repealed in short order ... especially once citizens tasted the benefits of the FairTax."
Reminds me of what they used to say about the income tax. It's only for the current emergency. We'll repeal it after the War is over. It will only affect the top 5% of wage earners and it will never be more than 2% of income. Yeah right.