If you're not averse to card, there's a 1/96th Saturn 1B at
http://www76.pair.com/tjohnson/sat1bm.html. And if you
are averse to card, you could always print out the patterns, transfer them to sheet styrene and or tubing, scratchbuild some details, use aftermarket bits and pieces for others (i.e., RealSpace Models excellent 1/96th-scale CSM) and at the end of the day, you'd have a unique model.
If you're interested, I have a couple of photos of my build-up of the card SA-205, the launch vehicle for Apollo 7, posted in my album at
http://www.cardmodels.net/phpbb2/album_personal.php?user_id=370. It should be noted that I modified and accurized the plans quite a bit for my build, and I added a lot of scratchbuilt detail. It's all card, except for some aluminum foil I used to cover the first-stage rocket nozzles.
I also modified the plans and built SA-210, the Saturn 1B used to launch the American part of the Apollo-Soyuz Test Project, but I haven't posted any photos of it yet.
Good luck.
David Hanners
Minneapolis