There are extensive discussions out there online of various iterations of Specialized bikes and their history. When Mike Sinyard initially set out to sell framesets and bikes, he enlisted Tim Neenan of Lighthouse Cycles after having had a custom touring frame built for him. The story I read is that the Expedition was based on that custom frame. Neenan also designed the original Sequoia and Allez frames. The earliest of the latter model were built by Yoshi Konno of 3Rensho and are very much sought-after; allegedly a small number of Sequoias were also built by Mr. Konno. Production realities led to contracts with Miyata and other high-quality Japanese makers.
Neenan is also credited with designing the original Stumpjumper. There are some who contend he borrowed heavily from the design of Tom Ritchey, but it IS fair to say he went to Japan and worked out how to mass-produce a mountain bike. This was probably the bike that catapulted the company forward and was their highest profile item.
Neenan's designs would later be refined and modified by Jim Merz (who is around on this forum as [MENTION=566038]Portlandjim[/MENTION]) and later by Mark DiNucci. Frame production shifted to Taiwan at some point in the '80s, and in interviews it has been observed that Specialized personnel personally oversaw some of the processes to sweat the details.
In no particular order -
The 1987-1989 Sirrus uses the same Giant-built-in-Taiwan frameset as the Allez of those years, but with somewhat softer paint and Shimano 105 rather than 600 components. My '88 Sirrus was a revelation - it is absolutely one of the very best riding bikes I have ever had under me, and only the presence in my stable of a Neenan-built Lighthouse with near identical geometry but clearance for larger tires has be considering selling it.
Grant Petersen of Rivendell has in the past described the early '80s Sequoia as the finest production sports-touring bike ever sold.
Do a long trawl of the bikeforums archives searching for model names, Neenan, Merz, etc. For that matter, a series of Google searches will turn up a lot of other stuff on this subject.
Which Specialized bike did you wind up winning at auction? Pictures, pretty please!