Speak of the devil and he shall appear ;-)

Funnily enough I saw yet another iteration of Alien yesterday, a DCP which appeared similar - but not the same - to the BD colouring. It was quite pleasingly balanced, though perhaps still a little cool for some tastes.

Anyway, having seen this film theatrically three times in its original version (twice on celluloid), I personally favour the laserdisc colouring as the overall truest, albeit with the occasional wobbles. Perhaps a next step would be to obtain a copy of this book if you don't already have it:

http://www.amazon.co.uk/Alien-Movie-Richard-J-Anobile/dp/0708816886

Subject to the limitations of the printed page, it gives a good flavour of what an original film print would have looked like (the short version is it's much like the laserdisc, only pushed slightly further towards green).

As far as versions go, I'm an original theatrical man all the way (for both films). It's your project of course, but that would be my suggested starting point, which could then extend to other versions.

Anyway, let me know if I can help in any way. I've no shortage of (otherwise) useless knowledge and opinion on this subject...