AAARGH! I knew it - Dan is a ming-reading JEDI!!!
No kidding: We DEFINITELY need the Narcissus to make the Alien line-up complete (Prometheus would be a fine addition, too, BTW). There is a looooong thread on theRPF where a group of outstandingly talented and reputated people are making a studio-scale Narcissus replica kit using all the different model bits and pieces used on the real thing. It is HUGE, to say the least. One of the test-builders is Lee Stringer. I have sent him some links to the BSG and Buck paper models the good guys at zealot have made and I really hope this creates some interest (he likes builds by fans).
Anyway, there is plenty of reference pictures including some orthos which could be used for a paper version.
Albeit, this is something I am thinking of to do, but not now. So if anyone is interested in making her, please do it. The basic shape is not very difficult. The ship comes to life with the texture. Did you know that the model from "Aliens" is a different one than the one from "Alien"? Well, I didn't.