For enough money upfront I'll get started today. For something really out of the norm a good salesperson should have gotten the customer to agree to an amount of money that would make it well worth it, whatever the task may be. I think for any outrageous example you come up with the cost will bring the customer back to reality.
It's dishonest to pitch it as a product you're selling when the technology to build it doesn't even exist yet. You can't say "Sure, we can do that for xxx million dollars and ten years", because you don't know if you'll have it all figured out even after xxx million and ten years, because nobody knows what would actually be required to produce that product. There may be some theory, but if that theory is erroneous for your application and you placed bets on it, you're screwed.
You have to pitch as a research investment. If a company wants to give you money for that kind of research, that's great, but you really need to make clear that it's not something you can just go and implement even if you have an infinite supply of money.
