Great idea, and I agree the time to do this is now!
I truly believe that this will be the last realistic chance of seeing the original films available in the quality they deserve.
We really need to push this, and by that I mean press and sites like The Digital Bits and Home Theatre Forum who'd be sympathetic to 'the cause', from a film history perspective, rather than some stereotypically whiney 'fan boy' one which wouldn't get us anywhere, and people are tired of by now:
It's important not to appear pushy and demanding. Carefully state that Star Wars is part of film history and needs to be preserved and treated with the same care and respect as any other historically important film like Ben-Hur, Gone With The Wind, North By Northwest etc etc. Bring up how younger generations would likely be fascinated by seeing how the trilogy has developed over the years.
Mention also the people who did the work that went into the original FX shots (many of which were replaced with the SEs) should have their contributions recognised and preserved for future generations to appreciate.
Lastly, I think a mention of the capabilities of Blu-Ray to hold all versions of the films could be bought up. As an example mention the amazing Blade Runner 5-disc blu-ray set, as well as Close Encounters of the Third Kind, both with all their cuts included. I think the biggest 'push' for Lucasfilm would be the realisation that they'd sell FAR more copies of this if all cuts were included - something for everyone then and we're all happy, and Lucas is sitting there watching yet more cash pour in! If they just released the SE versions that are already available on DVD I don't think sales would be that amazing as people already have these versions in pretty good quality already.
The historical nature of these films really does demand a theatrical version restoration however, and I sincerely hope some bright spark at Lucasfilm has the balls to mention this to Mr Lucas. (Would he like it if one of his fav. Kurosawa films was colourised for example, and THAT became the only version available? Food for thought!).