It'll work, for a little bit... just like all cloaking. Except probably not as long, since he's only relying on his own data.
Really? Damn, I don't know much about blackhat. I'd pay somebody to learn how to do this, or if they could do this for me, even if it's for a short while. I have a campaign on Yahoo that's doing well, and would be able to make my money back on Google quick, if I could get past their QS. Instead I'm wasting money on landing pages, domains, webspace, etc.. when I don't have to with Yahoo. Not only that, I don't even know if this landing page will be "acceptable" with Google so that will require more testing.
What kind of time frame are you talking about 1 hr? or 24 hrs? If it was 24 hrs.+, it would be worth paying for this technique or somebody to do it.
I'll try to look into these methods more, but I don't know any programming so I doubt I'll get anywhere.