In any case, no this isn't actually interesting either— because you have to do as much work as the whole network to get ahead of it in terms of expectation. So you might as well say "you could go mine as much as the network until you get ahead of it"— something you can't do without more computing power than it (much more, in the case that you start far behind it) since the expected required computing power would be equal. The only change is the variance. (and indeed, you can construct some kind of not very interesting very low probability example out of the difference in variance, but like your fraudulent ECDSA cracker, its not very interesting in practice)