This collection of original art by Rick Sternbach was originally sold as eBay lot #331 in the Profiles in History Hollywood Auction #14. I recently bought it from the Movie Prop King, Jason White.
This is a great collection because it really shows the evolution of thinking during the design process. As indicated by the notes on the drawings, these were for the amazing Star Trek: TNG episode, "Unification: Part Two."
From these computer designs, it seems clear that Sternbach began by looking at the only other Vulcan ship ever seen in on-screen Star Trek: Andrew Probert’s Shuttlecraft from Star Trek: TMP. This design seems to be a fusion of the nacelles from that vessel with a Starfleet-style saucer section.
This next design shows a step in a new direction with a "warp ring" rather than nacelles. Interestingly, operating independently later on, Doug Drexler would give warp rings to the Vulcan ships on Star Trek: Enterprise as well.
The final product is a very unique and striking design that ushered in a whole "Next Generation" of Vulcan ships that were to come.