I also patch my clients not to accept time corrections from the bitcoin network and think that the clock skew acceptance built in to the bitcoin network is insane. Or at least silly and out dated.
It would be great if you contribute it back to core so that others can enable it as an option.
It is trivial, and probably wrong. But in util.cpp, replace the GetAdjustedTime() function with:
int64 GetAdjustedTime()
{
return GetTime();
}
When this came up on the mailing list the other day, I suggested that we scrap everything involving timekeeping in the client and protocol, and start over with the requirement and assumption that the local clock be correct. It wasn't a popular proposal, but I'm pretty sure it is still the right thing to do.