From an Honest Christian
First of all, I would just like to say that I am not here to fire an "unanswerable argument" at you. In all honesty, I would sadly have to say that I agree with your point about Christians being dishonest in their arguments. This is because so many Creationists are looking for that "unanswerable argument-" just that one "magic bullet" to trip up any and every evolutionist. And sadly, so many Christians use dishonest means in a search for that argument--they lie, embellishing their arguments or matching the so-called "evidence" to fit the account of Creation as mentioned in the Bible.
But maybe it's time for a different approach.
Have you ever realized that both creationists and evolutionists each have their own presuppositions when entering a debate? Both look at evidence for the origins of the earth through the microscope that fits their presuppositions--for Christians, it's the Bible; for evolutionists, it's a glass labeled "Darwin."
Throughout history, Creationists have assumed that they have found Noah's Ark, based on some shreds of wood, or a handprint of a human in the same rock as a dinosaur fossil, even though it is very vague.
But evolutionists have done the same--they have put together skeletons of both apes and humans saying that they belong, or have drawn a whole "ape man" based on a pig's jawbone.
One thing must have happened--either creation or evolution. And since no one was there at the beginning of time, it is not fair to assume that the evidence fits one or the other if we are cutting it to fit a template. It is fair to examine the evidence in the light of our presuppositions, to see whether or not it fits; it is quite different, and unfair, to cut it to fit.
So both creationists and evolutionists must ask themselves: Is it really about an "unanswerable question" that disproves evolution once and for all? Or is it time for both parties to start being honest, examining both sides and "speaking the truth in love"? I think the latter.