Thanks to Geoff Boucher of the invaluable LA Times Hero Complex, I found this intriguing audition where Kurt Russell reads for the part of Han Solo opposite William Katt of Greatest American Hero fame. Believe it or not, it is a real possibility that Kurt could have landed the Han role. Thankfully he didn't. He's a little too Dexter Riley in this reading, and too little Snake Plissken. I would argue that Russell had so much of the residual fairy dust from his Disney live action films, that he may have made a great Luke. He has the charm, he just lacks the ruggedness.
I'm a big fan of Russell's, but if I had seen this footage before watching Escape from New York or Tombstone even I would have had a hard time believing that Russell could emote "grimness."
I have also realized another thing after watching these, and other, auditions for Star Wars. I realized that had I been directing the films, the actors may have become frustrated with hearing a single piece of direction uttered by me. That phrase would have been, "FASTER...MORE INTENSE!" It's true of the Harrison Ford audition as much as it is of these. The actors just seem so calm when they are delivering these lines.