I realize I'm a fair bit late to discussion, but I just thought I should share this:

"Silent Drifting" from 1979.

Wookiepedia plot summary:
"After Han Solo used some skillful piloting of the Millenium Falcon to destroy some TIE fighter, Princess Leia mentioned that Jedi pilots developed that same maneuver and she tells of one particular event involving Obi-Wan Kenobi. Kenobi was traveling as a passenger on a pleasure cruiser when he was notified by Captain Quasar that Merson pirates had been spotted in the Merson asteroid field....."

It almost seems like it was written specifically to avoid any possible contradictions to Lucas' still developing canon (I'm guessing they were aware of ESB being in production at this time). It makes no reference to either the Clone Wars or Anakin. However it does show a considerably cockier Obi-Wan than we got in the PT, and it's interesting how he was simply travelling as a passenger on a "pleasure cruise." It's quite the deviation of the monk-like Jedis of the PT. Obi-Wan does however turn down an "addictive stimulant" at some point, so he's still the disciplined warrior that was implied in the OT.
Obi-Wan also seems to be wearing a costume somewhat similar to what Luke ended up with in ROTJ. Which is interesting considering that this was written in 1979.

I also found a interesting pre-prequel reference to C-3PO's origins:

According to some notes made by Lucas in 1977 he was constructed at a Cybot Galactica plant on the planet Affa in 112 BBY.
http://starwars.wikia.com/wiki/Affa
(The EU has apparently retconned this into the TPM/PT lore so that he was originally built on Affa only to later be dismantled and discarded on the streets of Mos Espa where Anakin eventually found and rebuilt him.)