Zhosho made a nice Sovereign-class starship (of the Enterprise-E's sistership, the Yamato) some years ago: www.geocities.jp/ikenohata2005…
Unfortunately, the download links seem to be gone, but near the bottom of this page: www.geocities.jp/ikenohata2005… you can find his e-mail adress (just replace the [at] part with @) so maybe you can ask him if he could send you the files?
But of course, maybe you can find a different papercraft Enterprise-E on other websites too?
I'm sorry I can't help you better than this...! (