I'm sorely lacking in studio scale model knowledge, so I always assumed that the Tantive IV was a tiny little model, since the star destroyer chasing it was so monumentally huge (seemingly :lol) in the film.
The Tantive IV model was ILMs first model built (or started) for Star Wars and cost approximately 25% of the entire model building budget for the film. It was built over approximately the last 5 months of 1975. But it wasn't built as the Tantive IV. It was actually supposed to be used as "The Pirate Ship" aka "Millennium Falcon". That's why it was built so huge. It was originally intended to be used a lot on screen. Also, the scale of the ship was completely different during it's initial build.
In late 1975, just as they were putting the final touches on the model, someone working on the production in the UK saw some images (I personally believe they saw pictures of the Colin Cantwell concept model), and told Lucas they though it looked like the Eagle from Space:1999. So Lucas order a re-design of the ship. They sawed off the front cockpit and radar dish and used them on the redesigned Millennium Falcon that we know today. They rest of the model was eventually modified and put back into the film as Princess Leia's Tantive IV.
There's an excellent publication that discusses this in detail, including some fantastic new images. I believe the authors are members over on the Starship Modeller forums, and I bet they are here also.
"Sci-fi & Fantasy Modeller, Volume 5" which features an article entitled "A Boy, a Girl, and a Universe... A Look Back At The Making of Star Wars - 30 Years Later" by Paul Taglianetti and Gene Kozicki. Published in 2007.
One of the many cool images that make the above publication well worth buying... shows the
original Millennium Falcon.
TheModelShopMan - Fantastic build... can't wait to see the finished product. I'm always asounded by your builds.
Leif (from a transplanted Norwegian family)