Here's the drunken outtakes from a champagne commercial. Orson mentions that the champagne is fermented in the bottle, but it's pretty clear he is too. Many of you will know this as the "MWAHAAAAAAAAAAA, THE FRENCH" clip and you'd be right. This is actually the cleanest copy of the footage I've seen yet.
And here is an audio recording of a radio commerical for Sugar-Free 7-Up. It's not a drunken outtake or anything, it's a real ad that got real airplay. And it's got some of the most incredible purple prose ever written about a goddamn diet soft drink. However, he sells it. My god does he ever sell it! For some insane reason he could pull it off, as ludicrous as it was. That was his skill there.
We all know the frozen peas outtakes where Orson is acting as grammar diva and all-around diva ("Come on, fellas, you're losing your heads! I wouldn't direct any living actor like this in Shakespeare!") and here we have Orson even further lost than that in his fermenting bottle, but still, when he did a read for real (or when they could finally cobble together a working take in post) he was on. He was a darn good pitchman.
I couldn't find Maurice LaMarche teaching you how to talk like Orson Welles (he does teach you how to talk like William Shatner) but I did find a clip of him and Rob Paulsen sitting around a Starbucks talking like Pinky and the Brain. The mic picks up a lotta wind so don't listen to it too loudly, but the stuff you can hear is pretty funny.