BAC and its effects are well-documented and the effects are fairly consistent with most people so although I haven't seen what you're asking for I'm sure there's reams of data on it. I've called in a few myself, guys weaving all over on the interstate during rush hour, things like that. Safe to say those guys are well above 0.08.
And to seafire's OP, one of the issues with DUI for marijuana is that the dose/response effects are not nearly as consistent over the whole population. There's a blood concentration number that's been selected and is used for DUI but it's not backed by anywhere near the amount of data that BAC effects are so it's being challenged in court. Marijuana advocates maintain that the number is arbitrary, too low, and not backed by data. So the court challenges will continue.
