conclusion: sha-2(56) reasonably secure (thanks DeathAndTaxes for explaining the research). Reason for doubt (and also LTC popularity): GPU miner denial. Centralization by ASIC seems to be a myth so far.
case closed. jgarzik will win
the bet against @dakami (if Kaminzki has the balls to take it, which doesn't seem to be the case. But maybe he has no bitcoins, who knows).